[show abstract][hide abstract] ABSTRACT: Hunter syndrome (or mucopolysaccharidosis type II [MPS II]) arises because of a deficiency in the lysosomal enzyme iduronate-2-sulfatase. Short stature is a prominent and consistent feature in MPS II. Enzyme replacement therapy (ERT) with idursulfase (Elaprase®) or idursulfase beta (Hunterase®) have been developed for these patients. The effect of ERT on the growth of Korean patients with Hunter syndrome was evaluated at a single center. This study comprised 32 patients, who had received ERT for at least 2 yr; they were divided into three groups according to their ages at the start of ERT: group 1 (<6 yr, n=14), group 2 (6-10 yr, n=11), and group 3 (10-20 yr, n=7). The patients showed marked growth retardation as they got older. ERT may have less effect on the growth of patients with the severe form of Hunter syndrome. The height z-scores in groups 2 and 3 revealed a significant change (the estimated slopes before and after the treatment were -0.047 and -0.007, respectively: difference in the slope, 0.04; P<0.001). Growth in response to ERT could be an important treatment outcome or an endpoint for future studies.
Journal of Korean medical science 02/2014; 29(2):254-60. · 0.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: A 21-year-old man with diabetic ketoacidosis (DKA) displayed short and clubbed fingers and marked eyebrow, which are typical of Hajdu-Cheney Syndrome (HCS). Laboratory findings confirmed type 1 diabetes mellitus (DM). After conservative care with hydration and insulin supply, metabolic impairment was improved. Examinations of bone and metabolism revealed osteoporosis and craniofacial abnormalities. The mutation (c.6443T>G) of the NOTCH2 gene was found. The patient was diagnosed with HCS and DM. There may be a relationship between HCS and DM, with development of pancreatic symptoms related to the NOTCH2 gene mutation.
Journal of Korean medical science 11/2013; 28(11):1682-1686. · 0.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: Purpose: This study analyzed and evaluated the demographic, clinical, and cytogenetic data [G-banded karyotyping and array-based comparative genomic hybridization (array CGH)] of patients with unexplained developmental delay or intellectual disability at a single Korean institution. Materials and Methods: We collected clinical and cytogenetic data based on retrospective charts at Ajou University Medical Center, Suwon, Korea from April 2008 to March 2012. Results: A total of 190 patients were identified. Mean age was 5.1±1.87 years. Array CGH yielded abnormal results in 26 of 190 patients (13.7%). Copy number losses were about two-fold more frequent than gains. A total of 61.5% of all patients had copy number losses. The most common deletion disorders included 22q11.2 deletion syndrome, 15q11.2q12 deletion and 18q deletion syndrome. Copy number gains were identified in 34.6% of patients, and common diseases among these included Potocki-Lupski syndrome, 15q11-13 duplication syndrome and duplication 22q. Abnormal karyotype with normal array CGH results was exhibited in 2.6% of patients; theses included balanced translocation (n=2), inversion (n=2) and low-level mosaicism (n=1). Facial abnormalities (p<0.001) and failure to thrive were (p<0.001) also more frequent in the group of patients with abnormal CGH findings. Conclusion: Array CGH is a useful diagnostic tool in clinical settings in patients with developmental delay or intellectual disability combined with facial abnormalities or failure to thrive.
Yonsei medical journal 11/2013; 54(6):1463-70. · 0.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: Pseudohypoparathyroidism (PHP) is defined as resistance toward parathyroid hormones. PHP and pseudopseudohypoparathyroidism (PPHP) are rare disorders resulting from genetic and epigenetic aberrations within or upstream of the GNAS locus. This study investigated the clinical characteristics and performed a molecular analysis of PHP and PPHP.A total of 12 patients with (P)PHP from 11 unrelated families (4 with PHP-Ia, 6 with PHP-Ib, and 2 with PPHP) were characterized using both clinical and molecular methods. Clinical features included the presenting symptoms, Albright hereditary osteodystrophy features, and resistance to hormones. Comprehensive analysis of the GNAS and STX16 loci was undertaken to investigate the molecular defects underlying (P)PHP.All PHP-Ib patients displayed hypocalcemic symptoms. All PHP-Ia patients showed resistance toward TSH, in addition to PTH. In most patients with PHP, when the diagnosis of PHP was first established, hypocalcemia and hyperphosphatemia were associated with a significant increase in serum PTH levels. One patient with PHP-Ia was diagnosed with growth hormone deficiency and showed a good response to human recombinant growth hormone therapy. 6 patients with PHP-Ia and PPHP showed 5 different mutations in the GNAS gene. 5 patients with PHP-Ib displayed a loss of differentially methylated region (DMR) imprints of the maternal GNAS. One PHP-Ib patient showed a de novo microdeletion in STX16 and a loss of methylation of exon A/B on the maternal allele. No patients revealed paternal disomy among 4 patients with PHP-Ib.Identification of the molecular causes of PHP and PPHP explains their distinctive clinical features and enables confirmation of the diagnosis and exact genetic counseling.
[show abstract][hide abstract] ABSTRACT: The natural progression of the severe form of mucopolysaccharidosis II in children is a rapid decline of neurodevelopmental function with hydrocephalus. Recombinant human iduronate-2-sulfatase enzyme replacement therapy (ERT) under a standard regimen seems to have limited effect. Therefore, we determined whether early, high-dose ERT attenuated ventriculomegaly and histologic abnormalities in the brains of IdS-knockout mice. IdS-knockout mice received saline or recombinant human IdS (0.5/1.0/2.0 mg kg(-1)) intravenously once weekly, starting at 4 weeks of age and continuing until 20 weeks. ERT with 2.0 mg kg(-1), but not 0.5 or 1.0 mg kg(-1), significantly attenuated enlarged ventricles, as confirmed by in vivo 7-teslar brain magnetic reasonance image (MRI) at 20 weeks. However, neuronal cytoplasmic vacuolization and morphological alteration in the purkinje cells on brain histology and glycosaminoglycan (GAG) levels in brain homogenates were reduced in mice receiving ERT at lower dose than 2.0 mg kg(-1). Additionally, GAG levels significantly correlated with the percent volume ratio of ventricle to whole brain. These results suggested that high-dose systemic ERT started early in life could be a promising therapeutic modality for improving neurologic dysfunction including ventriculomegaly in children with severe Hunter syndrome.Journal of Human Genetics advance online publication, 5 September 2013; doi:10.1038/jhg.2013.92.
Journal of Human Genetics 09/2013; · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Kabuki syndrome (KS) is a rare genetic disease with a distinctive dysmorphic face, intellectual disability, and multiple congenital abnormalities. KS is inherited in an autosomal dominant manner. As the primary cause of KS, MLL2 mutations have been identified in 56-76% of affected individuals who have been tested, suggesting that there may be additional genes associated with KS. Recently, a few KS individuals have been found to have de novo partial or complete deletions of an X chromosome gene, KDM6A, which encodes a histone demethylase that interacts with MLL2. Nevertheless, mutations in MLL2 are the major cause of KS. Although there are a few reports of KS patients in Korea, none of these had been confirmed by genetic analysis. Here, we report a case of a Korean patient with clinical features of KS. Using direct sequencing, we identified a frameshift heterozygous mutation for MLL2: (c.5256_5257delGA;p.Lys1753Alafs*34). Clinically, the patient presented with typical facial features, and diagnosis of KS was based on the diagnostic criteria. While KS is a rare disease, other malformations that overlap with those found in individuals with KS are common. Hence, the diagnosis of KS by mutational analysis can be a valuable method for patients with KS-like syndromes. Furthermore, in the near future, other genes could be identified in patients with KS without a detectable MLL2 mutation.
Korean Journal of Pediatrics 08/2013; 56(8):355-8.
[show abstract][hide abstract] ABSTRACT: Osteogenesis imperfecta (OI) comprises a heterogeneous group of disorders characterized by bone fragility, frequent fractures, and low bone mass. Dominantly inherited COL1A1 or COL1A2 mutations appear to be causative in the majority of OI types, but rare recessively inherited genes have also been reported. Recently, SERPINF1 has been reported as another causative gene in OI type VI. To date, only eight SERPINF1 mutations have been reported and all are homozygous. Our patient showed no abnormalities at birth, frequent fractures, osteopenia, and poor response on pamidronate therapy. At the time of her most recent evaluation, she was 8 yr old, and could not walk independently due to frequent lower-extremity fractures, resulting in severe deformity. No clinical signs were seen of hearing impairment, blue sclera, or dentinogenesis imperfecta. In this study, we describe the clinical and radiological findings of one Korean patient with novel compound heterozygous mutations (c.77dupC and c.421dupC) of SERPINF1.
Journal of Korean medical science 07/2013; 28(7):1107-10. · 0.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant disorders in humans. NF1 is caused by mutations of the NF1 gene. Mutation detection is complex owing to the large size of the NF1 gene, the presence of pseudogenes, and the great variety of mutations. Also, few probable genotype-phenotype correlations have been found in NF1. In this study 78 Korean patients from 60 families were screened for NF1 mutations. Mutation analysis of the entire coding region and flanking splice sites was carried out and included the use of a combination of reverse transcription polymerase chain reaction, multiplex ligation probe amplification, or fluorescence in situ hybridization. Mutation spectrum and genotype-phenotype relationship were assessed. Fifty-two distinct NF1 mutations were identified in 60 families. The mutations included 30 single base substitutions (12 missense and 18 nonsense), 11 missplicing mutations, seven small insertion or deletions, and four gross deletions. Sixteen (30.8%) mutations were novel; c.1A>G, c.2033_2034insC, c.2540T>C, c.4537C>T, c.5546G>A, c.6792C>A, and c.6792C>G were recurrently identified. The mutations were evenly distributed across exon 1 through intron 47 of NF1, and no mutational hot spots were found. A genotype-phenotype analysis suggests that there is no clear relationship between specific mutations and clinical features. This analysis revealed a wide spectrum of NF1 mutations in Korean patients. As technologies advance in molecular genetics, the mutation detection rate will increase. Considering that 30.8% of detected mutations were novel, exhaustive mutation analysis of NF1 may be an important tool in early diagnosis and genetic counseling.
[show abstract][hide abstract] ABSTRACT: CATCH 22 Syndrome is caused by chromosome 22q11.2 microdeletion, characterized by developmental abnormalities of the third and fourth pharyngeal pouches. It has a prevalence estimated at 1:3,000-1:9,000. Most deletions occurs sporadic, but autosomal dominant inheritance observed in 6-10% of cases. CATCH22 often diagnosed due to hypocalcemia during neonatal period or decreased immunity or facial defect, so it is very rare being diagnosed CATCH22 in adulthood. We report a 57 year old female who referred to mental change due to hypocalcemia and is diagnosed CATCH22. She was presented with hypoparathyroidism, single kidney due to renal agenesis, and mild facial defect. Our patient responded well to calcium and vitamin D treatment and she is on follow-up in outpatient clinic.
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Mucopolysaccharidosis II (MPS II, Hunter syndrome) is a rare X-linked lysosomal storage disorder caused by the deficiency of iduronate-2-sulfatase (IDS). In affected patients, glycosaminoglycan (GAG) accumulates in the lysosomes of many organs and tissues contributing to the pathology associated with MPS II. The objective of this phase I/II clinical study was to evaluate the efficacy and safety of recombinant human iduronate-2-sulfatase (idursulfase beta, Hunterase(R)) in the treatment of MPS II. METHODS: Thirty-one MPS II patients between 6 and 35 years of age were enrolled in a randomized, single-blinded, active comparator-controlled phase I/II trial for 24 weeks. Patients were randomized to active comparator infusions (N=11), 0.5 mg/kg idursulfase beta infusions (N=10), or 1.0 mg/kg idursulfase beta infusions (N=10). The primary efficacy variable was the level of urinary glycosaminoglycan (GAG) excretion. The secondary variables were changes in the distance walked in 6 minutes (6-minute walk test, 6MWT), echocardiographic findings, pulmonary function tests, and joint mobility. RESULTS: Patients in all three groups exhibited reduction in urine GAG and this reduced GAG level was maintained for 24 weeks. Urine GAG was also significantly reduced in the 0.5 mg/kg and 1.0 mg/kg idursulfase beta groups when compared to the active comparator group (P = 0.043, 0.002, respectively). Changes in 6MWT were significantly greater in the 0.5 mg/kg and 1.0 mg/kg idursulfase groups than in the active comparator group (p= 0.003, 0.015, respectively). Both idursulfase beta infusions were generally safe and well tolerated, and elicited no serious adverse drug reactions. The most frequent adverse events were urticaria and skin rash, which were easily controlled with administration of antihistamines. CONCLUSIONS: This study indicates that idursulfase beta generates clinically significant reduction of urinary GAG, improvements in endurance as measured by 6MWT, and it has an acceptable safety profile for the treatment of MPS II.Trial registration: ClinicalTrials.gov: NCT01301898.
[show abstract][hide abstract] ABSTRACT: Prader-Willi syndrome (PWS) is a genetic disorder caused by the absence of expression of the paternal copy of maternally imprinted genes in chromosome region 15q11-13. The genetic subtypes of PWS are classified into deletion (∼70%), maternal uniparental disomy (mUPD; 25-30%), imprinting center defects (3-5%) and rare unbalanced translocations. Recently, Matsubara et al. reported a significantly higher maternal age in a trisomy rescue (TR) or gamete complementation (GC) by nondisjunction at maternal meiosis 1 (M1) group than in a deletion group. In the present study, we try to confirm their findings in an ethnically different population. A total of 97 Korean PWS patients were classified into deletional type (n=66), TR/GC (M1) (n=15), TR/GC by nondisjunction at maternal meiosis 2 (n=2), monosomy rescue or postfertilization mitotic nondisjunction (n=4) and epimutation (n=2). Maternal ages at birth showed a significant difference between the deletion group (median age of 29, interquartile range (IQR)=(27,31)) and the TR/GC (M1) group (median age of 35, IQR=(31,38)) (P<0.0001). The relative birth frequency of the TR/GC (M1) group has substantially increased since 2006 when compared with the period before 2005. These findings support the hypothesis that the advanced maternal age at childbirth is a predisposing factor for the development of mUPD because of increased M1 errors.Journal of Human Genetics advance online publication, 10 January 2013; doi:10.1038/jhg.2012.148.
Journal of Human Genetics 01/2013; · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Partial trisomy 8q is rare and has distinctive clinical features, including severe mental retardation, growth impairment, dysmorphic facial appearances, cleft palate, congenital heart disease, and urogenital anomalies. Partial monosomy 13q is a rare genetic disorder displaying a variety of phenotypic characteristics including mental retardation, dysmorphic facial features, and congenital anomalies. Here, we describe for the first time clinical observations and cytogenetic analysis of a patient with a concomitant occurrence of partial trisomy of 8q (8q21.3→qter) and partial monosomy 13q(13q34→qter). The patient was a female neonate with facial dysmorphia, agenesis of the corpus callosum, cleft palate, and congenital heart disease. G-band standard karyotype was 46,XX,add(13)(q34). To determine the origin of additional genomic gain in chromosome 13, array comparative genomic hybridization (CGH) was performed. Array CGH showed a 56.8 Mb sized gain on chromosome 8q and a 0.28 Mb sized loss on chromosome 13q. Therefore, the final karyotype of the patient was defined as 46,XX, der(13)t(8;13)(q21.3;q34). In conclusion, we described the clinical and cytogenetic analysis of the patient with concomitant occurrence of partial trisomy 8q and partial monosomy 13q delineated by array CGH. This report suggests that the array CGH would be a valuable diagnostic tool for identifying the origin of small additional genetic materials.
Annals of clinical and laboratory science 01/2013; 43(3):332-6. · 0.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Deletion and duplication of the -3.7-Mb region in 17p11.2 result in two reciprocal syndrome, Smith-Magenis syndrome and Potocki-Lupski syndrome. Smith-Magenis syndrome is a well-known developmental disorder. Potocki-Lupski syndrome has recently been recognized as a microduplication syndrome that is a reciprocal disease of Smith-Magenis syndrome. In this paper, we report on the clinical and cytogenetic features of two Korean patients with Smith-Magenis syndrome and Potocki-Lupski syndrome. Patient 1 (Smith-Magenis syndrome) was a 2.9-yr-old boy who showed mild dysmorphic features, aggressive behavioral problems, and developmental delay. Patient 2 (Potocki-Lupski syndrome), a 17-yr-old boy, had only intellectual disabilities and language developmental delay. We used array comparative genomic hybridization (array CGH) and found a 2.6 Mb-sized deletion and a reciprocal 2.1 Mb-sized duplication involving the 17p11.2. These regions overlapped in a 2.1 Mb size containing 11 common genes, including RAI1 and SREBF.
Journal of Korean medical science 12/2012; 27(12):1586-90. · 0.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: Precocious puberty is defined as breast development before the age of 8 years in girls. The present study aimed to reveal the diagnosis of Korean girls referred for precocious puberty and to compare the constitutional and endocrinological features among diagnosis groups.
The present study used a retrospective chart review of 988 Korean girls who had visited a pediatric endocrinology clinic from 2006 to 2010 for the evaluation of precocious puberty. Study groups comprised fast puberty, true precocious puberty (PP), pseudo PP, premature thelarche, and control. We determined the height standard deviation score (HSDS), weight standard deviation score (WSDS), and body mass index standard deviation score (BMISDS) of each group using the published 2007 Korean growth charts. Hormone tests were performed at our outpatient clinic.
The PP groups comprised fast puberty (67%), premature thelarche (17%), true PP (15%), and pseudo PP (1%). Advanced bone age and levels of estradiol, basal luteinizing hormone (LH), and peak LH after gonadotropin-releasing hormone stimulation testing were significantly high in the fast puberty and true PP groups compared with the control group. HSDS, WSDS, and BMISDS were significantly higher in the true PP group than in the control group (P<0.05).
The frequent causes of PP were found to be fast puberty, true PP, and premature thelarche. Furthermore, BMISDS were significantly elevated in the true PP group. Therefore, we emphasize the need for regular follow-up of girls who are heavier or taller than others in the same age group.
Korean Journal of Pediatrics 12/2012; 55(12):481-6.
[show abstract][hide abstract] ABSTRACT: Sotos syndrome is an overgrowth syndrome with characteristic facial dysmorphism, variable severity of learning disabilities and macrocephaly with overgrowth. Haploinsufficiency of the nuclear receptor SET domain-containing protein 1 (NSD1) gene located on 5q35 has been implicated as the cause of Sotos syndrome. This study was performed to investigate the mutation spectrum of NSD1 abnormalities and meaningful genotype-phenotype correlations in Korean patients with Sotos syndrome. Eighteen unrelated Korean patients with Sotos syndrome were enrolled for clinical and molecular analyses. Cytogenetic studies were performed to confirm 5q35 microdeletion, and NSD1 sequencing analysis was performed to identify intragenic mutations. NSD1 abnormalities were identified in 15 (83%) patients. Among them, eight patients (53%) had 5q35 microdeletions and the other seven patients (47%) had seven different NSD1 intragenic mutations including four novel mutations. The mutation spectrum of Korean patients with Sotos syndrome was similar to that of previous studies for Japanese patients. Height was significantly shorter and age of walking alone was significantly older in the microdeletion group compared with those in the intragenic mutation group. No significant differences were observed for other clinical characteristics between the microdeletion and intragenic mutation groups. Further studies with a larger number of patients will be necessary to draw conclusive genotype-phenotype correlations.Journal of Human Genetics advance online publication, 29 November 2012; doi:10.1038/jhg.2012.135.
Journal of Human Genetics 11/2012; · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is rare lysosomal storage disorder caused by N-acetylgalactosamine-6-sulfatase (GALNS) deficiency. Only a few MPS IVA cases have been reported in the Korean literature; there is a paucity of research about clinical or radiologic findings for this disorder. Therefore, we studied clinical findings, radiological features, and genetic data of Korean MPS IVA patients for determining factors that may allow early diagnosis and that may thus improve the patients' quality of life.
MPS IVA was confirmed via assay for enzymatic activity of leukocytes in 10 patients. The GALNS gene was analyzed. Patients' charts were retrospectively reviewed for obtaining clinical features and evaluated for radiological skeletal surveys, echocardiography, pulmonary function test, and ophthalmologic test results.
Nine patients had severe clinical phenotype, and 1 had an intermediate phenotype, on the basis of clinical phenotype criteria. Radiologic findings indicated skeletal abnormalities in all patients, especially in the hips and extremities. Eight patients had an odontoid hypoplasia, and 1 showed mild atlantoaxial subluxation and cord myelopathy. Genetic analysis indicated 10 different GALNS mutations. Two mutations, c.451C>A and c.1000C>T, account for 37.5% (6/16) and 25% (4/16) of all mutations in this samples, respectively.
An understanding of the clinical and radiological features involved in MPS IVA may allow early diagnosis of MPS IVA. Adequate evaluations and therapy in the early stages may improve the quality of life of patients suffering from skeletal abnormalities and may reduce life-threatening effects of atlantoaxial subluxation.
Korean Journal of Pediatrics 11/2012; 55(11):430-7.
[show abstract][hide abstract] ABSTRACT: Potocki-Lupski syndrome (PTLS [MIM 610883]) is a recently recognized microduplication syndrome associated with 17p11.2. It is characterized by mild facial dysmorphic features, hypermetropia, infantile hypotonia, failure to thrive, mental retardation, autistic spectrum disorders, behavioral abnormalities, sleep apnea, and cardiovascular anomalies. In several studies, the critical PTLS region was deduced to be 1.3Mb in length, and included RAI1 and 17 other genes. We report a 3-year-old Korean boy with the smallest duplication in 17p11.2 and a milder phenotype. He had no family history of neurologic disease or developmental delay and no history of seizure, autistic features, or behavior problems. He showed subtle facial dysmorphic features (dolichocephaly and a mildly asymmetric smile) and flat feet. All laboratory tests were normal and he had no evidence of internal organ anomalies. He was found to have mild intellectual disabilities (full scale IQ 65 on K-WPPSI) and language developmental delay (age of 2.2year-old on PRESS). Array comparative genomic hybridization (CGH) showed about a 0.25Mb microduplication on chromosome 17p11.2 containing four Refseq (NCBI reference sequence) genes, including RAI1 [arr 17p11.2(17,575,978-17,824,623)×3]. When compared with previously reported cases, the milder phenotype of our patient may be associated with the smallest duplication in 17p11.2, 0.25Mb in length.