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Location of the retinoblastoma susceptibility gene(s) and the human esterase D Locus
Abstract
Retinoblastoma occurs with increased frequency in children born with a deletion of the long arm of chromosome 13. Recent reviews have noted that the region 13q14 is consistently deleted in documented cases. Prometaphase and late prophase banding allowed Yunis and Ramsay to determine that a deletion in one patient included the sub-bands q14 . 12, q14 . 13, and q14 . 2, and a portion of q14 . 11 and q14 . 3. We report the results of similar cytogenetic techniques applied in the case of a 26 month old Caucasian female with unilateral retinoblastoma, moderate developmental delay, and subtle dysmorphology. Prometaphase banding of cultured skin fibroblasts revealed the karyotype: mos46,XX/46,XX,del(13)(q13 . 1q14 . 11). Only the sub-band q14 . 11 is deleted in both our patient and that of Yunis and Ramsay. The results are consistent with the localisation of the retinoblastoma susceptibility gene(s) in the sub-band 13q14 . 11. Electrophoretic analysis and activity assays of red blood cell esterase D are consistent with hemizygous expression of that marker in our proband. Comparison with published esterase D analyses in families with retinoblastoma permits the assignment of the esterase D locus to that same sub-band, 13q14 . 11.
... Since an experimental assay for the gene product of the RBI locus is not available, a cloned closely linked marker would provide a means to approach the retinoblastoma gene. Although other genes have been provisionally assigned to chromosome 13 (5,6), the gene for esterase D ESD is the only one proven to be tightly linked to retinoblastoma (7,8). Among informative families (extensively studied families of patients with retinoblastoma), there are no reported genetic recombinations between the ESD and RBI loci (9). ...
... Since this deletion affects the RBI locus and not the ESD locus, the ESD gene must lie closer to the centromere than RB). In a careful prophase banding analysis of several patients with deletions, Ward et al. (8) regionally mapped the ESD and RB) loci in the upper half of the q14. 11 subband of chromosome 13. ...
... Our preliminary results suggest that ESD is more than 5 kb from the RBI locus; otherwise we should have detected abnormalities in the ESD gene in some of the tumors examined. As described above, Ward et al. (8) have placed the ESD and RBI loci in the top half of the small chromosome subband 13q14.11, a region encompassing at most 3000 kb. Thus, we estimate that ESD and RBI are separated by more than 5 kb and less than 1500 kb. ...
The study of recessive oncogenes such as those responsible for retinoblastoma and Wilms tumor is difficult because the gene products involved are unknown and because the diseases are not associated with unique cellular or molecular phenotypes suitable for genetic manipulation. Since the gene for esterase D (ESD) is known to be tightly linked to the retinoblastoma locus (RB1) in the q14.1 band of chromosome 13, we have cloned the ESD gene from a human cDNA library by using oligonucleotides specific for a partial amino acid sequence of the purified enzyme to provide a genetic marker for further studies on retinoblastoma. The putative ESD gene codes for a message of 1.2 kilobases, which is present in all cell types examined, and maps to 13q14.1, thus confirming that it is the ESD gene. Restriction enzyme analysis reveals a restriction fragment length polymorphism with Apa I; this polymorphism results from the heterozygosity of 32% of the individuals tested and is shown to be useful in identifying carriers of the mutation responsible for retinoblastoma. A preliminary screen of 24 retinoblastoma tumors by Southern blot did not reveal any homologous deletions or rearrangements of the ESD locus.
... The WD families and 40 reference pedigrees from CEPH were typed for the chromosome 13 markers described in table 1. These markers were studied because, except for D13S1, they had been assigned to 13ql4-q22 by in situ or somatic cell hybridization (Cavenee et al. 1984; Ward et al. 1984; Dryja and Morton 1985; Leppert et al. 1986; Scheffer et al. 1987a) and thus were potentially useful for mapping WND (Bowcock et al. 1987a). D13S1 and D13S2 were at the extremes of the genetic map at 13ql2-ql3 and 13q22, respectively (Dryja and Morton 1985), and were used to orientate the other markers. ...
... The order of loci on the genetic map is consistent with the order predicted from their physical map assignments . RB and ESD were both initially assigned to 13ql4.11 by deletion mapping experiments using cells from patients with retinoblastoma (Yunis and Ramsay 1978; Sparkes et al. 1980; Ward et al. 1984), but more recent in situ hybridization experiments, using a cDNA probe for ESD, sublocalized the two loci to 13q14.2- q14.3 (Duncan et al. 1987). ...
Wilson disease (WD) is an autosomal recessive disorder resulting in an accumulation of copper in the liver, brain, and other organs. The WD locus (WND) has previously been linked to esterase D (ESD) and localized to 13q14-22. With the large Centre d'Etude Polymorphisme Humain cohort, a refined map of DNA markers from this region was constructed, with the following locus order: D13S1-D13S21-D13S22-D13S10-ESD-RB-WND-D 13S26-D13S12-D13S2. A significant excess of male recombination was observed between D13S21 and D13S22. Intervals distal to D13S22 showed an excess of female recombination. When these markers were tested on 19 WD families from a variety of ethnic backgrounds, the two closest loci were shown to be RB and D13S26. The retinoblastoma gene locus (RB) was shown to be proximal to WND at a distance of 4.4 centimorgans (cM), and D13S26 was placed distal to WND at a distance of 4.0 cM. ESD was assigned proximally at a distance of 9.4 cM. In all families studied WND was linked to one or more of the loci ESD, RB, or D13S26.
... A sialic 0-acetylesterase was first described by Shukla and Schauer in equine liver (16). In the course of studying a similar activity in human erythrocytes, we have discovered that it may be identical to the "nonspecific" esterase D. This enzyme is already known to be localized to human chromosome 13 (band 13ql4.11), in very tight linkage to a putative recessive "retinoblastoma gene" (17)(18)(19)(20)(21)(22)(23), and to the recessive gene causing Wilson disease (24). ...
... chromosome 13 (band 13q14.11) may be the cause of both hereditary and sporadic human retinoblastomas (17)(18)(19)(20)(21)(22)(23). Although the nature ofthe gene is unknown, its chromosomal localization was possible only because of a very tight linkage to esterase D. We have presented evidence here that this enzyme may be highly specific sialic acid O-acetylesterase. ...
The "nonspecific" esterases are a family of enzymes that were originally identified because of their reaction with synthetic O-acetyl ester substrates. While the electrophoretic polymorphisms of these enzymes have been extremely useful for genetic studies, their biological functions have remained completely unknown. Esterase D is characterized by its reactivity with 4-methylumbelliferyl acetate. This enzyme has recently been of particular interest because of its tight linkage to the putative recessive gene causing retinoblastomas, and to the recessive gene causing Wilson disease. We describe here the partial purification of a human erythrocyte esterase that appears to be highly specific for O-acetylated sialic acids. We next present evidence that suggests that esterase D is identical to this sialic acid-specific O-acetylesterase. First, both activities copurify from human erythrocyte lysates through several different purification steps, each of which use different principles of separation. Second, both activities show a remarkably similar profile of inhibition with a variety of different agents. Third, they both show a nearly identical heat-inactivation profile. This cytosolic sialic acid-specific O-acetylesterase appears to be involved in the "recycling" of O-acetylated sialic acid molecules. Thus, esterase D may be the first nonspecific esterase for which a specific biological role can be predicted.
... The locus contains the RB1 RBL gene, a tumor suppressor gene originally isolated by Friend et al. (15). LOH is caused by either deletion of the chromosomal locus (16) or mutation of the RB1 gene (17), and is detected not only in RBL but also in other malignancies such as osteosarcoma (18), breast cancer (19) and small cell lung cancer (20). Hereditary RBL patients are at an increased risk of developing osteosarcomas (7,21). ...
Little is known about the incidence of secondary neoplasms among survivors of retinoblastoma in Japan. The objective of our study was to analyze the cumulative incidence rate of secondary neoplasms following retinoblastoma and to investigate the risk factors of developing secondary neoplasms.
We conducted a retrospective cohort study of 754 retinoblastoma patients who visited the National Cancer Center Hospital in Tokyo between 1964 and 2007. The cumulative incidence rate curves were drawn using the competing risk method and compared with the Gray's test. Using competing risk regression analysis, multivariate analysis estimated the subdistribution hazard ratio of factors related to the development of secondary neoplasms.
The median length of follow-up was 108 months (0-594 months). Twenty-one (2.8%) patients developed 23 secondary neoplasms in total. The cumulative incidence rates of secondary neoplasms after retinoblastoma treatment were 2.4% at 10 years after diagnosis, 4.3% at 20 years, 6.4% at 30 years and 19.1% at 40 years. Ten patients (1.3%) died and 723 (95.9%) were alive without developing secondary neoplasms. The subdistribution hazard ratios of hereditary retinoblastoma and external beam irradiation were 4.85 (95% confidence interval = 0.74-31.85) and 4.76 (95% confidence interval = 0.69-33.09), respectively.
We demonstrated the cumulative incidence rate of secondary neoplasms following retinoblastoma in Japan. The subdistribution hazards ratios of hereditary retinoblastoma and external beam irradiation were high but not significant because of statistical power. The long-term follow-up of retinoblastoma survivors is warranted to understand secondary neoplasm risk.
... The esterase D gene has been mapped to the chromosome 13q14.11 region by correlating loss of the esterase D enzyme activity with known deletions on chromosome 13 of various mutant cells (3,4). To determine the location of the EL22 clone, several human mutant cell lines containing well-characterized deletions of chromosome 13 were selected. ...
Retinoblastoma, the most common intraocular tumor, represents one of the prototypes of inheritable cancers. To elucidate the mechanisms that give rise to this tumor, the retinoblastoma gene (RB) must be molecularly cloned. The difficulty encountered in cloning the gene is that little of its function or structure is known. The human esterase D gene, on the other hand, has been localized cytogenetically to the same sub-band of chromosome 13q14:11 as the RB gene. The esterase D gene thus provides a convenient starting point for cloning the RB gene. In this communication, we describe the isolation of the esterase D cDNA clone. Its identification is based on three lines of evidence. This cDNA encodes a protein immunologically related to the esterase D protein. The deduced amino acid sequences of this clone contain sequences identical to the three CNBr-cleaved peptides of the esterase D protein. This clone is mapped to the chromosome 13q14 region by Southern genomic blotting using different deletion mutants. The availability of this clone should allow for the cloning of the RB gene by chromosome walking; the diagnosis of genetic defects such as retinoblastomas and Wilson disease, whose genes are closely linked to the esterase D gene; and the exploration of the large family of human esterase genes.
... by Ward et al. (1984). Their case with retinoblastoma, being monosomic for 13q12--,q14.11, ...
To provide a rationale for gene dosage study of esterase D (EsD) in a case with trisomy 13 where the determination of gene dosage effects is complicated owing to the dimeric structure of EsD and the diversity in catalytic activity between different EsD phenotypes, we assayed red cell EsD activities and analyzed its isozyme patterns using starch gel electrophoresis and isoelectric focusing in five cases with partial trisomy 13 (Cases 1, 2 and 3) and full trisomy 13 (Cases 4 and 5). From mean EsD activities of three common EsD phenotypes (1, 2-1 and 2) in a total of 197 normal individuals, theoretical values of the total EsD activity and activity ratios of respective EsD isozymes were calculated for each genotype expected in a trisomy case. The observed total EsD activities and activity ratios of respective EsD isozymes, which were measured on starch gel zymograms by a spectrophotometric scanner, in the five cases led us to assume that Case 1 had EsD genotype 1-1-1, Case 2 genotype 2-2-1 and the remaining three cases genotype 2-1-1. The interpretations in three cases (Cases 1, 2 and 4) were further justified by the study of EsD phenotype in their parents. Isoelectric focusing, on the other hand, was insufficient to distinguish between genotypes 2-2-1 and 2-2 or between genotypes 2-1-1 and 2-1. These results suggested that the assay of EsD activity along with analysis of EsD isozyme pattern by starch gel electrophoresis is practically the best procedure to identify EsD genotype in a trisomy individual. Furthermore, this procedure proved to be useful to ascertain the parental origin of nondisjunction in some cases with trisomy 13.
... The extent of the deletion varies from patient to patient but in all cases part of chromosome band 13ql4 is missing. It was suggested by several authors that the frequently deleted region was the proximal part of 13ql4 (Yunis & Ramsay 1978;Ward et al., 1984, Sparkes et al., 1984 and in some cases the deletion is confined to that region (Yunis & Ramsay, 1978). Other reports suggest a more distal location of the critical region in 13q14 (Cowell et al., 1986b, c). ...
Fifty retinoblastoma families have been studied. In 41 it has been possible to determine the esterase-D phenotypes in all family members. Seven families were informative for the enzyme polymorphism and in all cases cosegregation of the retinoblastoma gene and esterase-D alleles was demonstrated, giving a lod score of 2.61. When combined with other published reports the cumulative lod score is 13.69 with no recombination in 45 meioses. In 10-15% of retinoblastoma families therefore, it is possible to offer prenatal diagnosis using the ESD protein polymorphism. The application of this test to the retinoblastoma population in the UK is limited by the low frequency of the rarer allele (0.116) and, as a result of genetic counseling, the smaller families generally associated with retinoblastoma.
Pediatric malignancies are markedly different from adult tumors, and the differences, along with a more concerted treatment network than typical for adult oncology, account for the significantly better survival rates and outcomes. The first reason is probably the different type of tumors which occurs in pediatrics. The solid malignancies of childhood are typically rapidly proliferating noncarcinomatous tumors, and the leukemias are clonal proliferation of early lymphoid progenitors. Both typically, harbor few if any genetic abnormalities. The slow-growing carcinomatous neoplasms, so characteristic of adulthood, are uncommon in pediatric oncology, and viruses, environmental toxins, and carcinogens appear, in general, to play a lesser role. Accordingly, when a child presents with a tumor where the accumulation of genetic changes rekindles a clonal carcinogenesis model reminiscent of adult carcinoma (1), the prognosis is usually very poor.
A candidate DNA sequence with many of the properties predicted for the retinoblastoma susceptibility (RB1) locus has been cloned (S. H. Friend, R. Bernards, S. Rogelj, R. A. Weinberg, J. M. Rapaport, D. M. Albert, and T. P. Dryja, Nature [London] 323:643-645, 1986). The large size of this gene (ca. 200 kilobases [kb]) and its multiple dispersed exons (Wiggs et al., N. Engl. J. Med. 318:151-157, 1988) complicate molecular screening strategies important in prenatal and presymptomatic diagnosis and in carrier detection. Here we used field inversion gel electrophoresis (FIGE) to construct a restriction map of approximately 1,000 kb of DNA surrounding the RB1 locus and to detect the translocation breakpoints in three retinoblastoma patients. DNA probes from either the 5' or 3' end of the gene were used to detect a 250-kb EagI restriction fragment in DNA from unaffected individuals. Both probes identified an additional hybridizing fragment in the DNA from each patient, permitting the breakpoints in all three to be mapped within the cloned RB1 gene. Analysis of the breakpoint in one translocation cell line allowed the RB1 gene to be oriented with its 5' end toward the centromere. The 5' end of the gene also appeared to be associated with a clustering of sites for several infrequently cleaving restriction enzymes, indicating the presence of an HpaII tiny fragment island. The detection and mapping of the translocation breakpoints of all three retinoblastoma patients to within the putative RB1 gene substantiated the authenticity of this candidate sequence and demonstrated the utility of FIGE in detecting chromosomal rearrangements affecting this locus.
The idea that inappropriate functions of specific genes can cause cancer has gained a lot of support from the study of acutely transforming retroviruses which carry oncogenes. Initially these oncogenes were isolated from avian retroviruses. Cellular homologues of these genes, termed proto-oncogenes, have been identified in eukaryotes. The demonstration that the introduction of activated oncogenes can confer a tumorigenic phenotype in certain cells has given rise to the concept that oncogenes act in a dominant manner. This appears to be true in chicken cells, for example, in which introduction of the src oncogene induces cancerous changes in host cells. This dominant transforming activity is not, however, a feature of all classes of genes that are involved in tumour development. Indeed, there is now a growing body of evidence to suggest that other classes of genes known as anti-oncogenes or suppressor genes may also function in the progressive series of events which leads to tumorigenesis.
Orbital tumors in the pediatric population are a rare event. The differential diagnosis for these tumors is broad, but only a small number of these lesions are malignant. In this chapter the chemotherapy used for the treatment of the following conditions will be discussed: (1) primary malignant orbital tumors such as rhabdomyosarcoma, lymphoma, and myeloid sarcoma; (2) malignancies that may metastasize to the orbit including neuroblastoma, Ewing sarcoma, and Wilms tumor; (3) malignancies that can invade the orbit such as retinoblastoma, optic nerve glioma, and esthesioneuroblastoma; and (4) nonmalignant processes including hemangiomas and Langerhans cell histiocytosis. A multidisciplinary team approach is essential to the treatment of these tumors in order to provide children with the best and most appropriate care possible. The treatments for these tumors are constantly evolving, and given the rarity of most of these conditions, understanding and improvement in outcomes will come about only with a cooperative, multidisciplinary approach within the context of large group trials.
We describe a genetic polymorphism of cytosol polypeptide with mol. wt. of 38,000 detected in phytohemagglutinin (PHA)-stimulated peripheral blood lymphocytes by two-dimensional gel electrophoresis. Three different electrophoretic phenotypes (type 1-1, 2-1, 2-2) of the polypeptide have been identified in a Japanese population. Family and population studies indicate that three phenotypes are determined by two common alleles at a single autosomal locus. Since the polypeptide is mainly present in cytosol of cells, we propose that the polypeptide be temporarily designated as cytosol polypeptide with mol. wt. of 38,000 (CP 38) and that the gene for CP 38 be designated as CP 38. The gene frequencies of two common alleles (CP 38
1 and CP 38
2) are 0.899 and 0.101, respectively, in a Japanese population. The data on gel filtration of cytosol proteins on a Sephadex G-100 column suggest that CP 38 exists as a dimer in the cytosol. CP 38 was observed in the wide range of different cells, including B-lymphoblastoid cells, adult skin fibroblasts, HeLa cells, and erythrocytes. In 11 out of 72 individuals, the phenotypes of CP 38 were different from those of adenosine deaminase which is similar to CP 38 in subunit size, cell distribution, and allele frequencies. These data indicate that CP 38 is a new polymorphic polypeptide encoded by an autosomal locus.
Das seltene Retinoblastom (Rb) wurde zu einem der wichtigsten Modelle der modernen Tumorgenetik; die Erforschung seiner familiären und seiner sporadischen Form führte zur Entdeckung der Tumorsuppressorgene. Die Art und die Vererbbarkeit der Rb-Veranlagung dürfte auch für weitere familiäre Tumorkrankheiten zutreffen. Die wichtigste medizinische Zielsetzung ist die primäre respektive die sekundäre Prävention des Tumors und der aufgrund der Rb-Disposition zusätzlich entstehenden Neoplasien. So wird die Betreuung der Rb-Patienten und ihrer Angehörigen zu einer Herausforderung für eine effektive interdisziplinäre Zusammenarbeit von verschiedenen Spezialisten. Der Humangenetiker trägt dazu mit seiner genetischen Beratung, inkl. Risikoprognosestellung sowie mit dem prä- und postnatalen molekulargenetischen Nachweis des Rb-Genes bei.
Summary
The rare childhood malignancy retinoblastoma (Rb) serves as one of the most important models in modern cancer genetics, since the study of its familial and sporadic occurrence has lead to the identification of the first so-called tumor suppressor gene. The nature of the Rb-pre-disposition and its mode of transmission could also hold true for many other familial cancers. An important goal of medical care is prevention, either by preventing the manifestation of retinoblastoma and of secondary malignancies related to the same predisposition or of their reaching an advanced stage of exacerbation. This can only be achieved by the close collaboration of several medical specialists. The human geneticist can contribute by offering genetic counselling, including risk estimates for offsprings of affected individuals, and by the molecular estimation of the Rb-trait.
Retinoblastoma is a highly malignant ocular tumor that has been known to be hereditary in some instances. New information from cytogenetic and molecular studies indicates that there is a retinoblastoma gene and that the mutant alleles are recessive. The wild-type gene appears to be a suppressor of this neoplasia, and, when both alleles are lost, malignancy develops.
Fifteen patients with hematologic disorders showed abnormalities involving chromosome band 13q14. Nine patients had an interstitial deletion of this band, similar to that reported in some retinoblastoma tumors and as a constitutional abnormality in a small proportion of cases of familial retinoblastoma. In five patients, band 13q14 was involved in translocations and in one case there was a deletion of one chromosome #13 and a translocation involving the homologous #13. The diagnosis in the majority of our patients (11 of 15) was chronic lymphocytic leukemia. In these patients the abnormalities were detected in cultures stimulated with 4-phorbol 12-myristate 13-acetate (PMA). It is possible that the utilization of this agent is a fundamental requirement for the reliable demonstration of abnormalities involving 13q14 in patients with B-cell malignancies. The incidence of abnormalities involving 13q14 and their significance in the development of neoplasias, other than retino-blastoma, is discussed.
Pulmonary surfactant, a protein-phospholipid mixture, maintains surface tension at the lung epithelium/air interface preventing alveolar collapse during respiration. For mammals appropriate developmental production of surfactant is necessary for adaptation to the air breathing environment. Deficiency of pulmonary surfactant results in respiratory distress syndrome (RDS), a leading cause of death in premature infants. Recently, three lung-specific pulmonary surfactant proteins designated SP-A, SP-B, and SP-C have been described. Cloned sequences for the genes that encode each of these proteins have been partially characterized in humans and other species. Analysis of interspecific backcross mice has allowed us to map the chromosomal locations of these three genes in the mouse. The gene encoding SP-A (Sftp-1) and the gene encoding SP-C (Sftp-2) both map to mouse chromosome 14, although at separate locations, while the gene encoding SP-B (Sftp-3) maps to chromosome 6. The mouse map locations determined in this study for the Sftp genes are consistent with the locations of these genes on the human genetic map and the syntenic relationships between the human and the mouse genomes.
Deletions of the 3p chromosome region and molecular alterations of the tumor suppressor genes RB1 and TP53, located, respectively, at 13q14 and 17p13, are well-documented in small cell lung cancer (SCLC). Because of technical difficulties, karyotypes of primary SCLC specimens are rarely reported. In this study, detailed cytogenetic analysis was performed on 13 early passage SCLC cell lines and fresh specimens, including 4 lung primaries. Numerous chromosome alterations were found, even in newly diagnosed primary tumors. Consistent with previous molecular studies, chromosomal losses of 3p (13 cases) and 17p13 (12 cases) were frequently observed. Numerical losses of chromosome 13 and structural rearrangements affecting 13q14 were identified in 10 specimens. In addition, losses of chromosome 5 and structural alterations of 5q occurred in 12 tumors; among these, 9 displayed losses of region 5q13-q21. Double minutes were found in 4 cases (3 of 5 specimens from patients who received prior cytotoxic therapy but only 1 of 8 from untreated patients). DNA analysis revealed amplification of either MYC1 or MYCN in cells from each of these 4 tumors. Overall, the cytogenetic findings underscore that progression of SCLC involves multiple genetic changes and suggest further that a tumor suppressor gene(s) on 5q may contribute to SCLC tumorigenesis.
We report on a patient with bilateral microphthalmia and unusual cataracts with a de novo pericentric inversion of chromosome (2)(p21q31). A literature review of previous associations of eye abnormalities and anomalies of chromosome 2 suggests probable gene locations for eye development.
A new two-dimensional isoelectric focusing method was developed to identify the human esterase D (EsD) subunits from the homodimeric and heterodimeric forms of five EsD phenotypes. EsD polymorphism was also analyzed by one-dimensional isoelectric focusing under reducing and mild denaturing conditions to study the influence of dithiothreitol and low concentrations of urea on the focusing pattern of the EsD dimers.
Serotonin (5-hydroxytryptamine) functions as a neurotransmitter and a hormone. Its diverse actions are mediated by at least seven distinct cell surface receptor subtypes. The serotonin receptor subtype 2 (gene symbol HTR2) is a G-protein-coupled receptor, expressed primarily in the cerebral cortex, where upon stimulation it stimulates the hydrolysis of inositol phospholipids. We have mapped the HTR2 locus to human chromosome 13 and to mouse chromosome 14 by somatic cell hybrid analysis. Linkage studies in CEPH families, using a PvuII RFLP detected with the HTR2 probe, revealed tight linkage between HTR2 and ESD, the locus for esterase D. The most likely position for HTR2 is between ESD and RB1, the retinoblastoma-1 gene. The homologous loci in mouse, Rb-1 and Esd(Es-10) are on mouse chromosome 14, close to ag, agitans, a recessive neurological mutation. Having mapped Htr-2 to mouse chromosome 14, we predict that it falls into this known conserved gene cluster.
Cytogenetic analysis was performed on 16 primary tumors, 2 effusions, and 3 cell lines from 21 patients with non-small cell lung cancer (NSCLC). In 20 patients specimens were obtained prior to initiating cytotoxic therapy. Extensive clonal chromosome alterations were found in all cases. The most frequent numerical changes were polysomy 7 and polysomy 20 (each seen in 12 specimens). In addition, tumor cells from another six cases exhibited partial trisomy 7, with the shortest region of overlap (SRO) at 7p11-p13. Rearrangements of chromosomes 1, 3, 6, 8, 11, 15, 17, and 19 were each observed in nine or more tumors. Breakpoints were clustered at several chromosomal sites, including 1p13, 3p13, 15p11-q11, 17p11, and 19q13. Recurrent loss involving 1p, 3p, 6q, 11p, 15p, 17p, and 19q were each seen in at least eight cases. The SRO of 3p losses was at band 3p21. Double minute chromosomes were found in three tumors. Overall, our findings indicate that even though karyotypes in newly diagnosed NSCLC are very complex, recurrent cytogenetic changes can be identified. The high incidence of loss of 17p (14 of 21 specimens) appears to be compatible with reports implicating the TP53 gene (at band 17p13) as a frequent site for genetic alteration in lung cancer. Moreover, the recurrence of loss of 3p (12 cases) and 11p (10 cases) is also consistent with recent molecular evidence. The existence of other "hot spots" for cytogenetic change, particularly those involving specific regions on chromosomes 7, 15, and 19, warrants further molecular investigation of these sites in NSCLC.
We evaluated the pregnancies of 427 women who conceived through artificial insemination by donor (AID) at our clinic over a 12-year period. Initial phone contact was followed by a questionnaire. Outcome was known for 594 of the 606 pregnancies, with a total of 502 live-born children including 15 sets of twins. The spontaneous abortion rate was 16.5%, with no difference between fresh- and frozen-semen pregnancies. Significant correlations were found between spontaneous abortion rate and maternal age (P less than .001) and spontaneous abortion rate and cycle of conception (P less than .025). Follow-up was completed on 481 children, among whom the following were found: one chromosomal anomaly, 22 major congenital anomalies, four children with possibly syndromic conditions, and 38 with minor congenital anomalies. Of the school-aged children, 5.8% had recognized learning disabilities and 10.5% were considered gifted by their schools. We also investigated the psychological impact of AID on each family. The majority of couples (71.7%) informed their obstetricians of the AID. Half of the couples did not tell any family or friends. Many couples did not (47%) or probably did not (14%) plan to tell their children of their origins. The divorce rate among those with AID children was 7.2%, which was significantly less (P less than .01) than that in a matched population. Psychological counseling specifically related to AID was sought by 2.8% of the couples. We conclude that AID children are at similar risk for congenital anomalies as normally conceived children, but they experience lower rates of family dissolution.
High-resolution banding, specific for electron microscopy, was applied to chromosomes of synchronized blood lymphocytes obtained from a child with bilateral retinoblastoma. Ultrastructural analysis of the subbands in region q14.1, after synchronization and immunochemical banding, showed that the deletion in the abnormal chromosome 13 corresponds to subband 14.11, thus evidencing that the retinoblastoma gene is located within subband q14.11. This first application to a diagnostic problem of immunochemical banding suggests that, coupled with electron microscopy, this banding provides a higher resolution than that obtained with light microscopy and should be useful to pinpoint important localizations.
The notion that genetic damage is the underlying cause of cancer comes from two apparently contradictory lines of evidence on the nature of carcinogenesis. On the one hand, many genomic changes found in malignant cells, such as point mutations, amplification, translocation, and various other rearrangements induced chemically or by retroviruses, have been shown to result in the activation of a set of genes termed oncogenes [1]. These genes, when introduced into target cells either as part of a virus of by DNA transfection can confer neoplastic transformation on the target cells. The existence of these oncogenes suggests that tumorigenicity may be dominant in nature. On the other hand, there is equally compelling evidence to suggest that recessive genomic changes may underlie the neoplastic phenotype of tumor cells.
Molecular studies of tumors arising during childhood have provided insights important for our understanding of the genetic
and cellular events that now seem likely to mediate the development of many different malignancies. Of particular interest
have been recent studies using recombinant DNA technology to study the pressure genetic alterations now thought to be central
features of oncogenesis. Oncogenes and recessive cancer genes, first recognized to be of clinical importance during the study
of Burkitt's lymphoma and retinoblastoma, are now thought to play a role in the development of most, if not all, tumors. Studies
to identify more effective approaches to cancer prevention, detection, staging, and treatment are now seeking to build upon
an understanding of those genetic alterations. It can be expected that pediatric oncology will once again play a pivotal role
as these studies mature into clinical trials. [J Natl Cancer Inst 81:404–408, 1989]
High resolution karyotype was performed in 13 retinoblastoma patients. A mosaic pattern for del(13)(q14.1;q14.3) was found in a girl with sporadic bilateral retinoblastoma and midface dysmorphism. In addition, 162 cases of 13q aberrations were reviewed, including 140 retinoblastoma patients and 22 non-penetrance 13q14 deletions. Some epidemiological and genetic involvements are discussed.
The retinoblastoma (Rb) gene is the prototype for a class of recessive human cancer genes in which loss of activity of both normal alleles is thought to be associated with tumorigenesis. Sixteen of 40 retinoblastomas examined with a complementary DNA probe shown to be the Rb gene had identifiable structural changes of the Rb gene including in some cases homozygous internal deletions with corresponding truncated transcripts. An osteosarcoma also had a homozygous internal deletion with a truncated transcript. In addition, possible hot spots for deletion were identified within the Rb genomic locus. Among those tumors with no identifiable structural changes there was either absence of an Rb transcript or abnormal expression of the Rb transcript. Comparison of the structural changes in the tumor cells and fibroblasts of certain patients provided support for Knudson's two-hit hypothesis for the development of retinoblastoma at the molecular level. The ability to detect germline structural deletions in fibroblasts from some patients with bilateral retinoblastoma also indicates that the isolated gene is useful for diagnostic purposes.
A candidate DNA sequence with many of the properties predicted for the retinoblastoma susceptibility (RB1) locus has been cloned (S. H. Friend, R. Bernards, S. Rogelj, R. A. Weinberg, J. M. Rapaport, D. M. Albert, and T. P. Dryja, Nature [London] 323:643-645, 1986). The large size of this gene (ca. 200 kilobases [kb]) and its multiple dispersed exons (Wiggs et al., N. Engl. J. Med. 318:151-157, 1988) complicate molecular screening strategies important in prenatal and presymptomatic diagnosis and in carrier detection. Here we used field inversion gel electrophoresis (FIGE) to construct a restriction map of approximately 1,000 kb of DNA surrounding the RB1 locus and to detect the translocation breakpoints in three retinoblastoma patients. DNA probes from either the 5' or 3' end of the gene were used to detect a 250-kb EagI restriction fragment in DNA from unaffected individuals. Both probes identified an additional hybridizing fragment in the DNA from each patient, permitting the breakpoints in all three to be mapped within the cloned RB1 gene. Analysis of the breakpoint in one translocation cell line allowed the RB1 gene to be oriented with its 5' end toward the centromere. The 5' end of the gene also appeared to be associated with a clustering of sites for several infrequently cleaving restriction enzymes, indicating the presence of an HpaII tiny fragment island. The detection and mapping of the translocation breakpoints of all three retinoblastoma patients to within the putative RB1 gene substantiated the authenticity of this candidate sequence and demonstrated the utility of FIGE in detecting chromosomal rearrangements affecting this locus.
A heritable mutation predisposes an individual to certain childhood malignancies, such as retinoblastoma and Wilms' tumor. The chromosomal locations of the genes responsible for the predisposition are known by linkage with chromosomal deletions and enzyme markers. A study of these tumors in comparison to the normal constitutional cells of the patients, using enzyme and DNA markers near the predisposing genes, has shown that these genes are recessive to normal wild-type alleles at the cellular level. Expression of the recessive phenotype (malignancy) involves the same genetic events that were observed in Chinese hamster cell hybrids carrying recessive drug resistance genes. In both the experimental and clinical situations, the wild-type allele is most commonly eliminated by chromosome loss with duplication of the mutant chromosome. Simple chromosome loss and mitotic recombination have been documented in both systems. In the remaining 30% of cases, inactivation or microdeletion of the wild-type allele are assumed to be responsible for expression of the recessive phenotype. Osteosarcoma is a common second tumor in patients who have had retinoblastoma. Studies with markers in osteosarcoma show that these tumors also result from unmasking of the recessive phenotype by loss of the normal allele at the retinoblastoma locus, whether or not the patient had retinoblastoma. Subsequent chromosomal rearrangements and amplification of oncogenes that occur in these homozygous tumors provide progressive growth advantage. In other malignancies, in which studies have so far focused on oncogene amplification and chromosomal rearrangements, unmasking of recessive mutations may also be the critical initiating events.
In situ hybridization of a cDNA probe for the esterase D gene (ESD) was carried out on human chromosomes. The probe hybridized most strongly to 13q14.2 and 13q14.3. This observation raises doubts concerning the most recently published assignment of ESD to 13q14.1. A deletion in an individual with retinoblastoma was reported to separate the closely linked ESD and retinoblastoma (RB1) loci, placing ESD proximal to RB1. Quantitative in situ hybridization studies of this deletion do not confirm this interpretation. Rather, they suggest that ESD is missing from the deleted chromosome 13 and duplicated on the normal homolog. From these findings, we conclude that the deletion in this individual cannot be used to determine the orientation nor the sublocalization of ESD and RB1 within the 13q14 region.
The gene encoding human esterase D (EsD), a member of the nonspecific esterase family, is a useful genetic marker for retinoblastoma (RB) and Wilson's disease. Previously we identified a cDNA clone from this gene and determined its chromosomal location. In this report, we present the complete cDNA sequence of the human EsD gene. A long open reading frame encoded a predicted protein of 282 amino acids with molecular weight of 30 kD. A computer-assisted search of a protein sequence data base revealed homology with two other esterases, acetylcholinesterase of Torpedo and esterase-6 of Drosophila. Homologous region were centered around presumptive active sites, suggesting that the catalytic domains of the esterases are conserved during evolution. Three genomic clones of this gene were also isolated and characterized by restriction mapping. At least ten exons were distributed over a 35-kb (kilobase pair) region; each exon contained an average of 100 basepairs (bp). A polymorphic site for Apa I, located within an intron of the esterase D gene, can be used to identify chromosome 13 carrying defective RB alleles within retinoblastoma families.
Mutational inactivation of the retinoblastoma susceptibility (RB) gene has been proposed as a crucial step in the formation of retinoblastoma and other types of human cancer. This hypothesis was tested by introducing, via retroviral-mediated gene transfer, a cloned RB gene into retinoblastoma or osteosarcoma cells that had inactivated endogenous RB genes. Expression of the exogenous RB gene affected cell morphology, growth rate, soft agar colony formation, and tumorigenicity in nude mice. This demonstration of suppression of the neoplastic phenotype by a single gene provides direct evidence for an essential role of the RB gene in tumorigenesis.
In this review of the recent literature, the contribution that the new techniques of molecular genetics has made in the analysis and diagnosis of human ophthalmic conditions is presented and discussed. Among the disorders reviewed are X-linked retinitis pigmentosa, Norrie's disease, gyrate atrophy and retinoblastoma, and there are also sections on crystallins and visual pigments.
We describe a new rare allele for esterase D (EsD) occurring in a Portuguese family with retinoblastoma in two generations.
Fifteen retinoblastoma patients were studied cytogenetically using G- and R-banding techniques. One patient showed 13q-mosaicism. It is suggested that a postzygotic deficiency in mosaic cases and in tumoral cells may be secondary to germinal mutation.
Wilson disease (WD) is an inherited disorder of copper metabolism that affects the brain, liver, and other organs. Our group recently reported close linkage between the locus for WD and a polymorphic red cell enzyme, esterase D (EsD), in a large inbred Israeli‐Arab lineage. We have subsequently studied two unrelated Druze kindreds in order to confirm this linkage and more precisely define the distance between the two loci. The maximum likelihood estimate of recombination was determined to be zero with lod scores of 1.48 and 1.06 in each Druze family, respectively. The combined maximum lod score based on pooled results from the Israeli‐Arab and Druze kindreds is 5.49 at θ = 0.03.
WD is one of a few autosomal recessive disorders that has been mapped by classical family study methods. In this paper, the merits for using large, inbred families in linkage studies of rare recessive disorders are discussed. Major considerations for pedigree selection are size and number of constituent nuclear families, number and distribution of affected individuals, and pedigree structure that may provide information for determination of phase between the disease and marker loci.
Human esterase D (carboxylesterase; carboxylic-ester hydrolase, EC 3.1.1.1), a genetic marker of retinoblastoma, was purified to biochemical homogeneity from erythrocytes. The purification scheme including carboxymethylcellulose, phenyl-Sepharose, chromatofocusing, and hydroxylapatite chromatographies resulted in a 10,000-fold purification of the enzyme with 15% recovery of total activity. The Km of esterase D was estimated to be 10 X 10(-6) M using 4-methylumbelliferyl acetate as substrate. The enzymatic activity was inhibited by p-chloromercuribenzoate and HgCl2, suggesting an important role of SH group(s) in enzyme function. Specific rabbit polyclonal and mouse monoclonal antibodies against esterase D were prepared and recognized either denatured or native human esterase D protein. Moreover, the polyclonal antibodies immunoprecipitated a polypeptide with a molecular mass of about 33-34 kDa from various cell lines of different mammalian species, indicating that the esterase D protein is highly conserved. The highest levels of this enzyme were found in liver and kidney. Furthermore, the expression of esterase D was enhanced 3-fold in a promonocytic cell line treated with phenobarbital but not with phorbol myristate acetate, suggesting that esterase D may have a role in detoxification. The availability of the homogeneous protein and its specific antibodies allows for cloning of the esterase D gene and facilitates studies of retinoblastomas.
The development of homozygosity or hemizygosity in the 13q14 region by deletion, mitotic recombination, or chromosomal loss has been interpreted as a primary event in retinoblastoma. This finding is consistent with the hypothesis that inactivation of both alleles of a gene located at 13q14.11 is required for tumorigenesis. Observations reported by Benedict and colleagues in one case of bilateral retinoblastoma, LA-RB 69, provided early evidence in favor of this hypothesis. By examining levels of esterase D, an enzyme also mapping to 13q14.11, it was previously inferred that one chromosome 13 was lost. Using a rabbit anti-esterase D antibody and the esterase D cDNA probe, we have found that low but detectable quantities of esterase D protein and enzymatic activity are present in tumor cells from LA-RB 69; fibroblasts from this patient contain two copies of the esterase D gene, indicated by heterozygosity at an Apa I polymorphic site within this gene; and tumor cells from the same patient are homozygous at this site, indicating loss and reduplication of the esterase D locus. These results demonstrate that one of the two esterase D alleles in this patient acted as a "null" or silent allele--that is, was present in the genome with markedly decreased protein expression. This mutant allele acted as a marker for tumor-associated loss of chromosome 13 heterozygosity, in concordance with previous proposals.
We describe the clinical and cytogenetic findings in a child with retinoblastoma and a translocation between chromosomes X and 13. The X;13 translocation in this patient does not involve band 13q14, the assigned locus for retinoblastoma.
Retinoblastoma is a childhood cancer, predisposition to which is inherited as an autosomal dominant trait. We used restriction-fragment-length and isozymic alleles of loci on chromosome 13 in five families predisposed to retinoblastoma, to provide identification before illness of persons likely to have tumors. The likelihood of disease was predicted in two cases, and freedom from disease in three. The calculated predictive accuracy was greater than 94 percent in cases with informative loci flanking the retinoblastoma (RB1) locus, and our prediction has been fulfilled in each such instance. A case that was informative at several loci indicated the occurrence of meiotic recombination, and accurate prediction was based on data obtained with DNA markers and isozymic forms of esterase D. The calculated predictive accuracy in another case, which was informative only for loci distal to the retinoblastoma locus, was about 70 percent. This patient was expected to acquire the disease but had not done so at the age of one year, illustrating the need for more markers that are also more informative and genetically closer to the retinoblastoma locus. These studies provide the basis for prenatal and postnatal prediction of susceptibility to inherited cancer using arbitrary recombinant DNA markers. Such predictions should make genetic counseling for familial retinoblastoma more accurate and lead to earlier tumor detection and more effective therapy.
Recent evidence indicates the existence of a genetic locus in chromosome region 13q14 that confers susceptibility to retinoblastoma, a cancer of the eye in children. A gene encoding a messenger RNA (mRNA) of 4.6 kilobases (kb), located in the proximity of esterase D, was identified as the retinoblastoma susceptibility (RB) gene on the basis of chromosomal location, homozygous deletion, and tumor-specific alterations in expression. Transcription of this gene was abnormal in six of six retinoblastomas examined: in two tumors, RB mRNA was not detectable, while four others expressed variable quantities of RB mRNA with decreased molecular size of about 4.0 kb. In contrast, full-length RB mRNA was present in human fetal retina and placenta, and in other tumors such as neuroblastoma and medulloblastoma. DNA from retinoblastoma cells had a homozygous gene deletion in one case and hemizygous deletion in another case, while the remainder were not grossly different from normal human control DNA. The gene contains at least 12 exons distributed in a region of over 100 kb. Sequence analysis of complementary DNA clones yielded a single long open reading frame that could encode a hypothetical protein of 816 amino acids. A computer-assisted search of a protein sequence database revealed no closely related proteins. Features of the predicted amino acid sequence include potential metal-binding domains similar to those found in nucleic acid-binding proteins. These results provide a framework for further study of recessive genetic mechanisms in human cancers.
Wilson disease (WD) is an autosomal recessively inherited disorder of copper metabolism for which the basic defect is still unknown. Twenty-seven autosomal markers were investigated for linkage in a large inbred kindred with affected individuals in two generations. Also, serum copper and ceruloplasmin were measured on all available members. Close linkage (theta = 0.06) with a logarithm of odds (lod) score of 3.21 was found between the gene for WD and the esterase D locus. Efficient detection of linkage was made possible by the use of a multisibship inbred pedigree. The discovery of a polymorphic marker genetically linked to the WD locus has profound implications both for investigation of the primary gene defect and for clinical services.
Retinoblastoma (Rb) occurs in hereditary, non-hereditary, and chromosomal deletion forms and the locus for the Rb gene (Rb-1) is closely linked to the locus for esterase D (ESD) assigned to the chromosome 13q14.11. We describe a patient who was predicted to have Rb from the genetic analysis of the chromosome and ESD phenotype. Furthermore, the gene for lymphocyte cytosol polypeptide with molecular weight of 64,000 (LCP1: McKusick catalogue No. 15343, 1983) was assigned to chromosome 13 by deletion mapping. A 3-month-old female had many characteristics of chromosome 13q-syndrome, including dolichocephaly, epicanthus, ptosis, depressed nasal bridge, micrognathia, short webbed neck, and short fifth fingers with clinodactyly and single crease. The karyotype of the patient was 46,XX,del(13) (q14.1-q32), though both the parents had normal karyotypes. As expected, the phenotype of ESD derived from one of the parents, the father in this case, was not detected in peripheral blood lymphocytes by two-dimensional gel electrophoresis (two-DE), indicating that ESD from the father was deleted in the abnormal chromosome 13. The possibility of paternity was calculated to be 0.996 based on the data using 22 genetic markers. Bilateral retinoblastomas could be diagnosed by ophthalmologic examinations before the manifestation of any clinical signs of the tumor and immediately intensive care was taken. In addition, the phenotype of LCP1 derived from the father was not expressed in the lymphocyte proteins from the patient. These data indicate that the gene for LCP1 (LCP1) is located in the region q14.1-q32 of chromosome 13 and may be a useful genetic marker for preclinical diagnosis of Rb.
Provided that there is no chromatid interference, no movement of chiasmata, and no discrepancies between meiotic and mitotic chromosome lengths, then genetic maps and recombination fractions may be directly derived from our meiotic chiasma distribution data. This is illustrated by male chiasma derived genetic lengths and recombination fractions along chromosome 13. The recombination fraction between 13p fluorescent markers and the proposed retinoblastoma locus at 13q14 is estimated at 0.27 to 0.37 and preliminary female chiasma studies suggest a recombination fraction of 0.5 between these two sites. Therefore, it seems unlikely that 13p fluorescent markers may be of any practical help in identifying retinoblastoma gene carriers. This is also borne out by the discordant segregation which has been found in six out of seven retinoblastoma families, which gives a calculated recombination fraction of 0.39 (SE 0.15), not significantly different from 0.5.
A 5-month-old girl suffering from bilateral retinoblastoma and severe psychomotor retardation with a long arm deletion of chromosome 13 was described. Cytogenetic study on peripheral leukocytes and skin fibroblasts, using a Giemsa-banding method revealed that bands q14 to q22 were deleted. The karyotype was expressed as 46XX del (13) (pter→q13::q31→qter).
• Two patients with retinoblastoma and an interstitial deletion of the long arm of chromosome 13 were studied using G-banded metaphase and prophase chromosomes. One patient showed several congenital defects, developmental retardation, and deletion of bands q14 and q21. The second patient showed mild developmental delay, a few minor congenital defects, and a loss of approximately half of band q14. On the basis of this study and nine others from the literature, it is now possible to tentatively assign a predisposition to retinoblastoma to deletion of a specific small region of chromosome 13.
(Am J Dis Child 132:161-163, 1978)
A 7-year-old girl with retarded physical and mental development was found, on chromosome determination, to have deletion of a segment of the long arm of chromosome 13 (13 q—). A precise chromosome identification was made on peripheral leukocytes by using a quinacrine banding technique. Because of previous reports of an association of the 13 q—chromosomal abnormality with retinoblastoma, an ophthalmologic examination was carried out. The patient was found to have bilateral microphthalmia, and multifocal, moderately well-differentiated retinoblastoma in the left eye.
A girl with retinoblastoma, mild psychomotor retardation, bifid uvula and clinodactyly of the fifth fingers is described. A chromosome analysis revealed a long arm deletion of a D chromosome. An autoradiographic analysis, as well as G- and Q-banding analyses indicated a 13q- chromosome. Measurements of length, surface and relative reflection of the different light and dark bands in the normal and abnormal chromosome 13 pointed to an interstitial deIetion, mainly of band q21 (46, XX, de1(13) (pter→q14:: q22→qter) The chromosome findings and the clinical features of the patient are discussed and compared with other reported cases.
This report compares the pathogenetic influences of selective deletion and triplication of chromosome 13 derived from a familial 12; 13 insertional translocation. In the proband a heritable chromosomal basis for his bilateral retinoblastomas is established [46, XY, del (13) (pter → q12.5::q22.→qter)mat], and in his sister the relatively modest effects of triplication of the mid–portions of 13q are demonstrated [46, XX, ins(12;13) (12pter→–12pll.2::13q22.1→13q12.5::12pll.2→12qter)mat]. Qualitative and quantitative gene marker studies and chromosomal staining techniques to differentiate timing of DNA replication failed to indicate functional gene changes about the breakpoints.
In the course of an investigation of karyotypes in patients with retinoblastoma, one was found in whom all cells showed a deletion in the longer arm of one of the large acrocentric chromosomes. Five other patients had normal karyotypes.
The writers wish to thank Dr White Franklin for drawing attention to case no. 1 and arranging for the biopsy, Dr Joy D. A. Delhanty for the fibroblast culture in case no. 1, Dr R. G. Chitham for the culture in case no. 6, Dr Sylvia D. Lawler for suggestions and Miss Dorothy Newlyn for family history investigations.
The work was carried out with the aid of a grant RG‐6984 from the United States Public Health Service.
New clinical and pathologic findings in patients with deletion of the long arm of chromosome 13 (13q-) include optic nerve hypoplasia and retinal dysplasia. Fibroblasts derived from patients with a 13q- syndrome with and without retinoblastoma, as well as from familial and sporadic retinoblastoma, are a useful model for the study of genetic susceptibility to the development of spontaneous and radiation-induced cancers. Fibroblasts from patients with hereditary retinoblastoma appear more radiosensitive than fibroblasts from patients with sporadic retinoblastoma or normal control patients.
A girl with sporadic unilateral retinoblastoma and mental retardation has an interstitial deletion in the long arm of chromosome
13. Her mother has a paracentric inversion of one chromosome 13; the deleted chromosome 13 in the daughter is derived from
the mother's normal chromosome 13.
Electorphoretic and quantitative assays of esterase D in a Caucasian family demonstrate the inheritance of a null allele, which was observed in the heterozygous state in six individuals.
In a series of eight patients with retinoblastoma, one was found to have a reciprocal translocation of chromosomes 1 and 13. The breakpoint on chromosome 13 is at band q12, which suggests that the retinoblastoma locus is less distal than previously thought.
Two patients with retinoblastoma and an interstitial deletion of the long arm of chromosome 13 were studied using G-banded metaphase and prophase chromosomes. One patient showed several congenital defects, developmental retardation, and deletion of bands q14 and q21. The second patient showed mild developmental delay, a few minor congenital defects, and a loss of approximately half of band q14. On the basis of this study and nine others from the literature, it is now possible to tentatively assign a predisposition to retinoblastoma to deletion of a specific small region of chromosome 13.
Karyotypes from 50 persons with retinoblastoma confirmed by histopathological examination were studied by conventional staining and Giemsa-banding techniques. Two chromosomal anomalies were found. An interstitial deletion of the long arm of No. 13 chromosome was identified by Giemsa-banding in the karyotypes from a boy with unilateral retinoblastoma. Another boy with unilateral tumor had a karyotype of 47,XXY. These findings provide additional evidence that a deletion of chromosome No. 13, most likely involving band 13q14, is associated with the development of retinoblastoma. In conjunction with other reports, our findings also suggest that retinoblastoma may be found more frequently in children with chromosomal aneuploidy.
An infant girl with failure to thrive and bilateral retinoblastoma had a translocation of the long arm of chromosome 13 to the short arm of the X chromosome, and possible loss of a portion of the q 14 band. The lack of other major organ malformations in this patient emphasized the importance of considering chromosomal aberrations as a possible etiology of retinoblastoma in patients with nonspecific psychomotor retardation.
Retinoblastoma occurs at a very high rate among two groups of genetically predisposed persons: those who inherit the tumor potential with a dominant mode of transmission, and those who bear a deletion of the long arm of chromosome 13 in all their somatic cells. The latter group is particularly important because it is the only instance in animal or man in which a specific chromosomal abnormality can occur prezygotically and consistently predispose to a specific tumor. We report below a new case of this deletion and consider its relation to previously reported cases and the relation between the two genetic . . .
This paper calls attention to the possible localization of a gene (or genes) involved in the development of retinoblastoma (Rb) on a circumscript region of 13q. Rb, an embryonic tumor, occurs most often in the unilateral (unifocal) nonhereditary form. Bilateral (multifocal) cases are considered hereditary, probably due to a single, not fully penetrant, autosomal dominant gene. In addition, sporadic bilateral Rb associated with a Dq- deletion has been reported in several patients. Speculation about the nature of the relevant genetic material presumably located in 13q14 leads to the following possibilities. If the relevant gene(s) had a function in normal retinal development, the deletion could cause a shortage of a gene product necessary for a stage of retinal differentiation. Incompletely differentiated embryonic cells may be more susceptible to tumor formation. Lele and colleagues, when reporting the first case of Dq- with Rb, suggested that the deletion might remove a normal allele and thus facilitate expression of the autosomal gene for Rb. This hypothesis is made unlikely by the consistently negative family histories for Rb in 10 cases with Dq-. Relative to the postulation of two mutational events (one germinal and one somatic, or both somatic) necessary for the development of Rb, one could consider the deletion to be equivalent to the first mutation, if the second mutation was to occur at a different gene site. The 13q14 deletion could be analogous to the autosomal dominant mutation, in that either mutation or deletion of a 'retinoblastoma gene' would produce the same clinical picture. A possible viral origin of this tumor may be correlated with the specific chromosomal change in two ways. Breakage in the proximal 13q region could activate an endogenous neutropic tumor virus; or an exogenous virus could have a specific binding or integration site in this region. Rb may not be single entity; the same phenotype could be due to multiple causes. Although the interstitial 13q- deletion appears to be a nonrandom and specific chromosomal change, it would be premature at this time to assign the retinoblastoma gene locus to this region.
G-band prophase chromosomes from synchronized cells permit a high degree of resolution not previously attained in the study of chromosome structure and birth defects in man.
We examined the diagnostic usefulness of thallium-201 scintigraphy in 200 patients with acute myocardial infarction. The scintiscans showed a defect, suggesting infarction in 165. In all 44 patients studies within six hours after onset of symptoms the scintiscans indicated a defect. Frequency of positive scans was significantly higher (90 of 96) in patients studies within 24 h after onset than in those (75 of 104) studied later (P < 0.01).
When scintigraphy was performed later than 24 h after onset of symptoms, questionable and negative scintiscans were obtained even in patients with moderately elevated transaminase levels. Twenty-eight patients received repeat scans, and within 24 h after onset of symptoms, the size of the defect tended to decrease, probably owing to regression of ischemia. Repeat scintiscans obtained later than 24 h showed fewer changes in defect size (P < 0.05). Thallium-201 scintigraphy gives optimum diagnostic information when performed within 24 h after onset of symptoms.
A new human esterase, designated esterase D, has been discovered using acetate and butyrate esters of 4 methyl umbelliferone as substrates to detect red cell esterase isozymes after starch gel electrophoresis. The isozymes of esterase D cannot be detected by conventional naphthyl ester azo dye coupling techniques and differ in several other properties from previously described human esterases. Three different commonly occurring electrophoretic types of esterase D have been identified and designated Es D 1, Es D 2 1 and Es D 2. Family studies indicate that they are determined by two alleles Es D1 and Es D2 at an autosomal locus. Es D2 was found with a frequency of 0.098 in Europeans and Blacks and 0.227 in Asiatic Indians. Esterase D isozymes were detected in all the human tissues examined. These included adult post mortem tissues, foetal livers, cultured fibroblasts and lymphocytoid cells. Preliminary work suggests that esterase D will be a useful marker in somatic cell hybridization experiments. The triple banded isozyme pattern seen in Es D 2 1 heterozygotes indicates that esterase D is a dimeric enzyme protein.
Two children with multiple congenital anomalies underwent enucleation for intraocular tumors. One child was a retarded, 30-month-old girl with hirsutism, low-set ears, enlarged heart, multiple skeletal defects, and advanced bilateral intraocular tumors. The second child was 11 months old and had multiple defects limited to the skeletal system and a unilateral intraocular tumor. In both cases, histopathologic examination showed undifferentiated retinoblastoma, and cytogenetic study revealed a deletion of the long arm of a group-D chromosome (46XXDq-).
Evaluation of three families with hereditary retinoblastoma demonstrates close linkage of the gene for this tumor with the genetic locus for esterase D. These results assign the gene for the hereditary form of retinoblastoma to band q14 on chromosome 13, the same region which is affected in the chromosome deletion form of this eye tumor, and therefore suggest a common underlying mechanism in the pathogenesis of these two forms of retinoblastoma.
The segregation of chromosomes 13 distinguishable by Q band fluorescent polymorphisms has been studied in three families with retinoblastoma. The recombination fraction for two of these families and four families previously reported did not differ significantly from 50%. Since a high recombination fraction has been predicted from chiasma frequency between the centromere of chromosome 13 and 13q14 these results neither confirm nor refute the location of the autosomal dominant gene predisposing to retinoblastoma in 13q14. The use of fluorescent markers is not suitable for early recognition of gene carriers in families with retinoblastoma.
A previously unpublished association of retinoblastoma and histiocytosis-X is described in a girl. In addition, chromosome analysis revealed a mosaicism of normal and abnormal mitoses. A deleted D-group chromosome (13q14→q31) was present.
Mouse-human cell hybrid clones retaining an inactive translocated chromosome involving the human X and 13 were isolated. Esterase D, a marker on the segment of chromosome 13 translocated to the X, was not expressed in these clones. These results provide genetic evidence for the spreading of inactivation into the autosomal segment in an inactive human X-autosome translocation.
Using a cell population with a high proportion of early mitotic cells and by examining more cells derived from peripheral lymphocytes, we found three cases with a 13q14 deletion mosaicism among fifteen retinoblastoma patients; one with a de novo 13/18 balanced translocation, and another with a monosomy 13(q13q21.2 or 21.3). The three patients with a 13q14 deletion mosaicism had sporadic retinoblastoma (two had bilateral and one unilateral retinoblastoma). The results indicate that 13q14 deletion mosaicism plays a major role in the etiology of this tumor.
In a patient with a 13qXp translocation and retinoblastoma the band associated with retinoblastoma (13q14) was clearly translocated intact to the X chromosome rather than being the breakpoint of the translocation. Genetic inactivation of the derivative X chromosome shown by late labeling and cell hybridization techniques in the predominance of cells indicated a functional monosomy for this segment as the most likely predisposing factor in producing retinoblastoma.
The expression of human esterase D was evaluated quantitatively and qualitatively in five persons with partial deletions or
duplications of chromosome 13. The results showed that the locus of this enzyme is at band 13q14. Deletion of this same band
in other subjects has been found previously to indicate a predisposition to the development of retinoblastoma, which was present
in the four individuals in this study who had partial deletions of chromosome 13. Because of this close synteny, esterase
D evaluation should aid in the diagnosis and genetic counseling of retinoblastoma.
Fluorescent markers on chromosome 13 have been used to study familial retinoblastoma. One family showed concordant segregation of a particular chromosome 13 and retinoblastoma from the affected parent to the affected children. In three other families, segregation was discordant. Meiotic crossing over with recombination is proposed as the explanation.
An infant girl suffering from bilateral retinoblastoma and psychomotor retardation with a translocation of the long arm of chromosome 13 to the short arm of the X chromosome was described. The break point was determined to locate in band 13. As the band q14 is probably intact, the position effect might have attributed to the formation of retinoblastoma in this case.
Evidence for a null allele at the esterase D (EC 3.1.1.1) locus New findings in the chromosome 13 long arm deletion syndrome and retinoblastoma
- Rs Sparkes
- S Targum
- E Gershon
- Gf Sensabaugh
- Mc Sparkes
- M Crist
- Rr Weichselbaum
- Zn Zabov
- Dm Albert
- Ah Friedman
- J Nove
- Jb Little
Sparkes RS, Targum S, Gershon E, Sensabaugh GF,
Sparkes MC, Crist M. Evidence for a null allele at the
esterase D (EC 3.1.1.1) locus. Hum Genet 1979;46:319-23.
Weichselbaum RR, Zabov ZN, Albert DM, Friedman AH,
Nove J, Little JB. New findings in the chromosome 13
long arm deletion syndrome and retinoblastoma
OpthalmolAAO 1979;86:1191-8.