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G. Filippi
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ABSTRACT: 265 hypogonadic Sardinian males, ascertained through military records of 600,000 conscripts approximately over the last thirty-seven years, were screened for their sex chromatin phenotype by buccal mucosa smears and for their karyotypes from peripheral blood lymphocyte cultures. 158 (59.4%) showed a XXY karyotype without mosaicismo, 5 XX and 1 XXYY karyotypes. Seven sex chromatin negative males had Kallmann's syndrome. This report summarizes the genetic and clinical data recorded in this population sample as opposed to those reported from fertility clinics.
Clinical Genetics 04/2008; 30(4):276 - 284. · 3.13 Impact Factor
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ABSTRACT: This report complements a series of clinical, cytogenetical, and psychological studies previously reported on a large Sardinian pedigree segregating for premutations and full mutations associated with the Martin-Bell syndrome (MBS). Using the StB12.3 probe, we report now the molecular classification of all of the critical members of the pedigree. These molecular findings are evaluated against the variable phenotypic manifestations of the disease in the course of a six-generation segregation of an MBS premutation allegedly present in a common female progenitor of 14 MBS male patients and 9 female MBS heterozygotes seen in the last two generations. The nature and stepwise progression of MBS-premutations toward the fully manifested Martin-Bell syndrome and the possibility of reverse mutational events toward the normal allele are discussed with respect to the application of the presently available diagnostic tools in genetic counselling.
American Journal of Medical Genetics 09/1996; 64(2):283-6.
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ABSTRACT: We used several microsatellite markers scattered along the X chromosome to search for linkage relationships in a large Sardinian pedigree segregating for nonspecific X-linked mental retardation (MRX). Markers DXS573 and AR, located at chromosomal subregions Xp11.4-p11.22 and Xq11.2-q12, respectively, were found to segregate in full concordance with the disease, leading to a LOD score of 4.21 at zero recombination value. Recombination with the disease was found with markers MAOB and DXS454 located at Xp11.4-p11.3 and Xq21.1-q22, respectively; accordingly, markers distal to Xp11.4 and Xq22 also segregated independently of the disease. These findings provide strong linkage evidence in favor of the localization of one MRX mutational site in the pericentromeric region of the human X chromosome, justifying the assignment of a new symbol (MRX26) to our pedigree. Finally, on the basis of the recombinational events observed in the Xq21-q22 region, we have been able to refine the assignment of marker DXS456 to Xq21.33-q22.
American Journal of Medical Genetics 08/1996; 64(1):107-12.
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American Journal of Medical Genetics 08/1996; 64(1):134-6.
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C Carbonara,
L Longa,
E Grosso,
G Mazzucco,
C Borrone,
M L Garrè,
M Brisigotti, G Filippi,
A Scabar,
A Giannotti,
P Falzoni,
G Monga,
G Garini,
M Gabrielli,
P Riegler,
C Danesino,
M Ruggieri,
G Magro,
N Migone
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ABSTRACT: To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation.
Genes Chromosomes and Cancer 02/1996; 15(1):18-25. · 3.31 Impact Factor
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ABSTRACT: We report on a Sardinian pedigree with congenital ichthyosis associated with normal levels of steroid sulfatase and a normal molecular pattern, as detectable with a cDNA probe for the steroid sulfatase (STS) gene. Though the pattern of transmission of the disease is consistent with X-linked recessive inheritance, this form of ichthyosis was found to segregate independently of genetic polymorphisms detected by probes of the region Xp22.3, where the STS locus has been mapped. The search for close genetic linkages with other polymorphic markers scattered along the entire X chromosome has so far been fruitless. For the time being, the main conclusion derived from these data is that STS deficiency is not a sine qua non for X-linked ichthyosis which may also result from a mutational event at an X-chromosomal site genetically unlinked to the STS locus.
American Journal of Medical Genetics 12/1995; 59(2):143-8.
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ABSTRACT: We report on a 20-month-old boy with skull malformations and motor delays. A diagnosis of Saethre-Chotzen syndrome was made in view of the clinical and neuroradiological signs. Other unusual findings were trigonocephaly and occipital dysplasia with medial schisis at the foramen occipitalis. The mother showed a mild expression of the syndrome.
American Journal of Medical Genetics 12/1992; 44(5):611-4.
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ABSTRACT: A large Sardinian family including 13 Martin-Bell syndrome (MBS) patients, several instances of normal transmitting males or females, and the G6PD-Mediterranean mutant segregating in some of its branches, has been thoroughly investigated with the hope of gaining further insight on the nature of the FRAX-mutation. All the MBS patients and the 15 obligate heterozygous women present in the pedigree could be traced back through their X-chromosome lineage to the same ancestress, who must have been heterozygous for a silent premutation at the FRAX-locus. This premutation appears to have turned into a true FRAX-mutation at least 9 times during the gametogenesis of the ancestress' X-related descendants of whom four are males. This finding alone suggests that the transition from the FRAX premutation to the true mutation can be the result of intra- as well as interchromosomal events. This conclusion is supported by the additional observation that the genetic phase between the FRAX and the G6PD loci remained unaltered when the transition occurred in a repulsion double heterozygote for the premutation and the G6PD-Mediterranean mutant. The data described are compatible with the hypothesis that MBS patients and normal transmitting males are, respectively, hemizygous for deletion or duplication products generated by aberrant recombination events at a highly recombinogenic site of the region Xq27-Xqter. The overall message stemming from this report is that no firm conclusion can be drawn on the genetic linkage between the FRAX-locus and other markers of this region until the nature of the FRAX-mutations and the mechanism of their occurrence are fully understood.
American Journal of Medical Genetics 10/1991; 40(4):387-94.
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ABSTRACT: One hundred forty-nine subjects from 18 families with fragile X [fra(X)] syndrome were evaluated for their neuropsychological, psychiatric, and physical characteristics. The 36 fra(X) males had intelligence quotients ranging from less than 20 to 61, which prevented the delineation of a reliable neuropsychological profile. Behaviour fitted DSM-III-R and ADI diagnostic criteria of autism in only 2 subjects, both with very low intelligence level (IQ less than 20). Of 36 heterozygotes (HZ), 22 had an IQ between 20 and 80 and 14 between 81 and 99. The neuropsychological profile of the latter was compared with IQ-age-environment-matched 14 normal females and 14 normal males. Significantly poorer results in HZ were found on immediate digit memory and on Raven's progressive matrices (a visuo-spatial test of logical capabilities). The latter result, in conjunction with those results on the Bender visual-motor gestalt test and on some WAIS subtests, suggests a frequent deficit in spatial capabilities in such subjects. Such results tended to be confirmed by the profiles of the 22 HZ with IQ 20-80. No psychiatric abnormalities were found in HZ, except in one subject with IQ less than 20 which fitted DSM-III-R and ADI criteria for autism. Typical physical manifestations, especially cranio-facial, were more frequently present in the HZ group with lower IQ. Subnormal IQ was probably the most reliable abnormality for the detection of HZ in 49 females at 50% and 25% risk of heterozygosity.
American Journal of Medical Genetics 09/1991; 40(2):234-43.
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ABSTRACT: A total of 9153 male subjects in mental institutions from six different Italian districts were screened for the presence of bilateral microorchidism, in order to detect Klinefelter syndrome. Among the 212 microorchidic patients found, 33 had an XXY karyotype (15.5%). Ninety-one Klinefelter patients with normal intelligence were also examined as a control group. Cytogenetical and clinical findings were compared in these two groups of patients and no difference was found. Two fra(x)positive subjects were found, one for each group of XXY patients; the influence of fra(x) mutation on their phenotype is discussed.
Clinical Genetics 04/1991; 39(3):189-93. · 3.13 Impact Factor
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ABSTRACT: The still debated question of whether the expression of mental retardation in heterozygous carriers of the Martin-Bell syndrome is influenced by X inactivation has been investigated in a group of phase-known double heterozygotes for the FRA-X mutant and the G6PD Mediterranean variant. In these individuals, the number of somatic cells (fibroblasts or red cells) with an active FRA-X chromosome could be assessed through the G6PD phenotype at the single-cell level. The data reported indicate a significant inverse correlation between the IQ level (as measured by the Wechsler-Bellevue test) and the percentage of fibroblast cells with an FRA-X active chromosome. In contrast, no significant correlation was found when the IQ level and red cell data were compared, thus suggesting the occurrence of somatic selection against hematopoietic stem cells with an active FRA-X chromosome.
The American Journal of Human Genetics 05/1990; 46(4):738-43. · 10.60 Impact Factor
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ABSTRACT: A terminal deletion in the short arm of chromosome 8 was found in a 2.5-year-old boy: 46,XY,del(8) (p22.0) and in a 1-year-old girl: 46,XX,del(8) (p23.1) with dysmorphic craniofacial features and developmental retardation. Erythrocyte GSR activities of the boy and of his parents were within normal limits. Vitamin K dependent coagulation factors in the girl and her parents gave normal results. Clinical findings were compared with previously reported cases and suggested a recognizable syndrome.
Clinical Genetics 05/1990; 37(4):271-8. · 3.13 Impact Factor
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ABSTRACT: Fourteen families with X-linked mental retardation (XMR) have been studied clinically and cytogenetically. All affected males failed to show a fragile site (FS) on Xq of their peripheral lymphocytes. Five families may be considered examples of Renpenning syndrome while the remaining may be divided in two groups: one of seven (type I) and one of two (type II). The seven families of type I had some physical features of the Martin-Bell syndrome but with normal to large sized testes whence the name of X-linked MR with slight macroorchidism (XMR +/- MO). The two families of type II showed unremarkable facial appearance, mild to moderate degree of MR and a certain microorchidism whence the possible name of X-linked MR with different degree of microorchidism (XMR +/- MiO).
Journal de génétique humaine 01/1988; 35(5):381-98.
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ABSTRACT: Eighteen families with X-linked mental retardation (MR) with or without macroorchidism, fragile-X positive at Xq27 (Martin-Bell syndrome) have been studied clinically and cytogenetically. All 58 affected males presented variable degrees of MR, fra(X) (q27) of their peripheral lymphocytes, macroorchidism in all adult patients with the exceptions of one with microorchidism as 47,XXY sex chromosome complement and the other with borderline testes, and characteristic facial appearance. The expression of the marker X in the heterozygotes seems to be more related to the mental development rather than the age of the individual. In two families the transmission of the syndrome through unaffected males seems probable.
Journal de génétique humaine 01/1988; 35(5):351-79.
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ABSTRACT: The analysis of two rodent X human somatic cell hybrids, carrying different inborn translocations of the human chromosome 14 long arm, has permitted us to narrow down the localization of the structural locus for alpha-1-antitrypsin (PI) to band 14q32.1, proximally to the highly polymorphic DNA locus D14S1 which has been localized by previous studies between 14q32.1 and 14q32.2. These data, evaluated in conjunction with other published information, suggest that the D14S1 locus is cytologically equidistant from both the PI locus and the complex locus for the immunoglobulin heavy chains (IGH) but, genetically, it appears much closer to the latter since the recombination frequency reported between the IGH complex and PI is six times greater than that between the IGH complex and D14S1 (lod score peaks respectively at 26% and 4% with narrow fiducial limits). The present report adds further strength to the frequently proposed hypothesis of a nonlinear relationship between cytologic and genetic distances of human genes. The possibility that this phenomenon may be a feature of frequent occurrence throughout the entire human genome is discussed.
Cytogenetics and cell genetics 02/1987; 44(1):32-40.
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ABSTRACT: We previously proposed the hypothesis that the primary expression of the defect in X-linked Duchenne muscular dystrophy (DMD) occurred in the myoblast, or muscle precursor cell. This was based on the observation that the number of viable myoblasts obtained per gram DMD muscle tissue was greatly reduced and those that grew in culture had decreased proliferative capacity and an aberrant distended flat morphology. Here we test that hypothesis by determining whether the expression of the myoblast defect is X-linked. Muscle cells were obtained from five doubly heterozygous carriers of two X-linked loci, DMD and glucose-6-phosphate dehydrogenase (G6PD), and compared with those from five sex- and age-matched controls heterozygous for G6PD only. A total of 1,355 individual clones were determined to be muscle and evaluated at the single cell level for proliferative capacity, morphology, and G6PD isozyme expression. The results demonstrate that the proportion of defective myoblast clones is significantly increased in DMD carriers. However, since this cellular defect does not consistently segregate with a single G6PD phenotype in the myoblast clones derived from any of the carriers, it is unlikely to be the primary expression of the DMD mutant allele.
Human Genetics 10/1986; 74(1):74-80. · 5.07 Impact Factor
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ABSTRACT: We previously proposed the hypothesis that the primary expression of the defect in X-linked Duchenne muscular dystrophy (DMD) occurred in the myoblast, or muscle precursor cell. This was based on the observation that the number of viable myoblasts obtained per gram DMD muscle tissue was greatly reduced and those that grew in culture had decreased proliferative capacity and an aberrant distended flat morphology. Here we test that hypothesis by determining whether the expression of the myoblast defect is X-linked. Muscle cells were obtained from five doubly heterozygous carriers of two X-linked loci, DMD and glucose-6-phosphate dehydrogenase (G6PD), and compared with those from five sex-and age-matched controls heterozygous for G6PD only. A total of 1,355 individual clones were determined to be muscle and evaluated at the single cell level for proliferative capacity, morphology, and G6PD isozyme expression. The results demonstrate that the proportion of defective myoblast clones is significantly increased in DMD carriers. However, since this cellular defect does not consistently segregate with a single G6PD phenotype in the myoblast clones derived from any of the carriers, it is unlikely to be the primary expression of the DMD mutant allele.
Human Genetics 08/1986; 74(1):74-80. · 5.07 Impact Factor
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ABSTRACT: The human gene for glucose-6-phosphate dehydrogenase (G6PD) has been subregionally mapped to band Xq28 by segregation analysis in rodent-human somatic cell hybrids [Pai, G. S., Sprinkel, J. A., Do, T. T., Mareni, C. E. & Migeon, B. R. (1980) Proc. Natl. Acad. Sci. USA 77, 2810-2813]. We have previously reported a common type of X-linked mental retardation associated with an inducible fragile site at Xq27-Xq28 segregates in a close linkage relationship with a G6PD variant, but the relative position of G6PD with respect to the fragile site has not yet been established. This fragile-X syndrome has been shown to be closely linked also to a Taq I restriction fragment length polymorphism detected by a cDNA probe for factor IX, and the latter locus has been mapped to the subtelomeric region Xq26-Xq28 [Camerino, G., Mattei, M. G., Mattei, G. F., Jaye, B. & Mandel, J. L. (1983) Nature (London) 306, 701-704]. The in situ hybridization studies reported here provide strong evidence that G6PD is located on the Xq telomeric fragment distal to the fragile site. These observations and the well-established knowledge that the genes for Deutan and Protan colorblindness are closely linked to G6PD, but segregate independently of factor IX deficiency, suggest that the fragile site associated with this type of X-linked mental retardation occurs in a region prone to high frequency of meiotic recombination.
Proceedings of the National Academy of Sciences 01/1985; 81(24):7855-9. · 9.68 Impact Factor
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ABSTRACT: A young girl with 46,XX,r(18)/46,XX/45,XX,-18 chromosome constitution is reported. She displays a slight degree of mental retardation. The line with the ring chromosome predominates in blood lymphocytes. In skin fibroblast culture the ring(18) line showed a constant decreasing trend, from 45% at the first passage, down to its disappearance at the 19th passage, where only 46,XX cells were observed. The child/mid parents' ratio of Peptidase A activity in red cells was 0.36. The Peptidase A activity in a fibroblast clone 46,XX,r(18) was 0.55 compared to the 46,XX line. These data suggest that the PEP A locus was lost in ring formation.
Clinical Genetics 09/1984; 26(2):156-60. · 3.13 Impact Factor
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ABSTRACT: A Sardinian pedigree described in 1964 for having been found to segregate at the X-linked loci for the Xga antigen, G6PD deficiency, Protan and Deutan color blindness, with an instance of recombination between the last two loci, was re-examined with respect to four common X-linked DNA polymorphisms detected by molecular probes homologous to critical subregions of the human X chromosome. Two branches of this pedigree--including the one with the Protan-Deutan recombinant--were found to segregate also for the common BamHI polymorphism identified with the cDNA probe pHPT-2 or the HPRT gene (Xq26). The analysis of the chromosome haplotypes in the male offspring of the phase known penta-heterozygous mother suggests that the probable order of the relevant loci is HPRT, Deutan, G6PD, Protan, Xq telomere. Though we are fully aware of the risks of generalizing the significance of observations made on a single exceptional pedigree, we believe that this report outlines the potential of families of the type described as research tools to resolve the linear order of tightly X-linked loci and to investigate the biology of genetic recombination in humans.
Human Genetics 02/1984; 65(3):295-9. · 5.07 Impact Factor
