PURPOSE: The objectives were to examine following 2 questions related to cognitive profile for the children with Williams syndrome (WS); 1) Is there a significant advantage for verbal IQ over performance IQ in WS?; 2) Is there selective impairment in visuospatial ability in the children with WS? MATERIALS AND METHODS: Five children with WS with the age of 90.86+/-20.73 months were compared with 12 children with Prader-Willi syndrome (PWS) or Down syndrome (DS) with comparable age and IQ. RESULTS: All 5 children with WS showed intellectual disability whose mean scaled scores were 15.71+/-9.27 in verbal subtests and 14.29+/-7.50 in performance subtests, which did not show significant difference. There was no significant difference in the total sum of scaled scores of verbal subtests among WS, PWS and DS. There was no selective impairment in subtests which represented visuospatial tasks for the children with WS. However, the scaled score of object assembly was significantly lower in WS (2.29+/-0.95) compared to that of PWS (4.75+/-2.77; P<0.05). CONCLUSION: The general notion that the children with WS would be relatively strong in verbal function when compared with their overall cognitive function was not observed in this study. The verbal function of the children with WS was not better when compared to the children with DS or PWS. There was no selective impairment of visuospatial function in the children with WS at this age. However, the visuospatial function was significantly low in the children with WS only when compared to the children with PWS.
Child ; Down Syndrome ; Humans ; Imidazoles ; Intellectual Disability ; Nitro Compounds ; Prader-Willi Syndrome ; Williams Syndrome

No abstract available.
Intellectual Disability ; Rubinstein-Taybi Syndrome*

Mental retardation is a disability characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and adaptive skills, which originates before the age of 18. The prevalence of mental retardation among elementary school children in Korea is estimated as 9~12/1,000. In most cases of mental retardation, the interplay of genetic and environmental influences remains poorly understood. However, recent advances in molecular genetic techniques have enabled us to understand more about the molecular basis of several genetic syndromes associated with mental retardation. This article presents a review of three common genetic conditions causing mental retardation-Down syndrome, fragile X syndrome, and Prader-Willi syndrome-with the summary of the effectiveness of early intervention for the children with mental retardation.
Adaptation, Psychological ; Child ; Down Syndrome ; Early Intervention (Education) ; Fragile X Syndrome ; Humans ; Intellectual Disability* ; Korea ; Molecular Biology ; Prader-Willi Syndrome ; Prevalence

BACKGROUND: To validate the clinical application of chromosomal microarray analysis (CMA) as a first-tier clinical diagnostic test and to determine the impact of CMA results on patient clinical management, we conducted a multicenter prospective study in Korean patients diagnosed as having developmental delay/intellectual disability (DD/ID), autism spectrum disorders (ASD), and multiple congenital anomalies (MCA). METHODS: We performed both CMA and G-banding cytogenetics as the first-tier tests in 617 patients. To determine whether the CMA results directly influenced treatment recommendations, the referring clinicians were asked to complete a 39-item questionnaire for each patient separately after receiving the CMA results. RESULTS: A total of 122 patients (19.8%) had abnormal CMA results, with either pathogenic variants (N=65) or variants of possible significance (VPS, N=57). Thirty-five well-known diseases were detected: 16p11.2 microdeletion syndrome was the most common, followed by Prader-Willi syndrome, 15q11-q13 duplication, Down syndrome, and Duchenne muscular dystrophy. Variants of unknown significance (VUS) were discovered in 51 patients (8.3%). VUS of genes putatively associated with developmental disorders were found in five patients: IMMP2L deletion, PTCH1 duplication, and ATRNL1 deletion. CMA results influenced clinical management, such as imaging studies, specialist referral, and laboratory testing in 71.4% of patients overall, and in 86.0%, 83.3%, 75.0%, and 67.3% of patients with VPS, pathogenic variants, VUS, and benign variants, respectively. CONCLUSIONS: Clinical application of CMA as a first-tier test improves diagnostic yields and the quality of clinical management in patients with DD/ID, ASD, and MCA.
Autism Spectrum Disorder ; Autistic Disorder ; Cytogenetics ; Diagnostic Tests, Routine ; Down Syndrome ; Humans ; Intellectual Disability ; Korea ; Microarray Analysis ; Muscular Dystrophy, Duchenne ; Prader-Willi Syndrome ; Prospective Studies ; Referral and Consultation ; Specialization

BACKGROUND: Microdeletion syndromes not detectable by conventional cytogenetic analysis have been reported to occur in approximately 5% of patients with unexplained mental retardation (MR). Therefore, it is essential to ensure that patients with MR are screened for these microdeletion syndromes. Mental retardation syndrome multiplex ligation-dependent probe amplification (MRS-MLPA) is a new technique for measuring sequence dosages that allows for the detection of copy number changes of several microdeletion syndromes (1p36 deletion syndrome, Williams syndrome, Smith-Magenis syndrome, Miller-Dieker syndrome, DiGeorge syndrome, Prader-Willi/Angelman syndrome, Alagille syndrome, Saethre-Chotzen syndrome, and Sotos syndrome) to be processed simultaneously, thus significantly reducing the amount of laboratory work. METHODS: We assessed the performance of MLPA (MRC-Holland, The Netherlands) for the detection of microdeletion syndromes by comparing the results with those generated using FISH assays. MLPA analysis was carried out on 12 patients with microdeletion confirmed by FISH (three DiGeorge syndrome, four Williams syndrome, four Prader-Willi syndrome, and one Miller-Dieker syndrome). RESULTS: The results of MLPA analysis showed a complete concordance with FISH in 12 patients with microdeletion syndromes. CONCLUSIONS: On the basis of these results, we conclude that MLPA is an accurate, reliable, and cost-effective alternative to FISH in the screening for microdeletion syndromes.
*Chromosome Deletion ; Classical Lissencephalies and Subcortical Band Heterotopias/genetics ; DiGeorge Syndrome/genetics ; Humans ; In Situ Hybridization, Fluorescence/*methods ; Laboratories, Hospital ; Mental Retardation/*diagnosis/genetics ; Nucleic Acid Amplification Techniques/*methods ; Prader-Willi Syndrome/genetics ; Williams Syndrome/genetics

Fragile X syndrome (FXS) is the most common monogenic form of inherited intellectual disability and autism spectrum disorder (ASD). More than 99% of individuals with FXS are caused by the unstable expansion of CGG repeats located within the 5'-untranslated region of the FMR1 gene. The clinical features of FXS include various degrees of cognitive deficit, physical, behavioral and psychiatric problems. Early treatment and prevention from having further affected children can be guided by molecular genetic testing of the FMR1 gene. The following guideline has combined the relevant research, guidelines and consensus worldwide, and summarized the genetic knowledge and clinical treatment for FXS in order to achieve a standardized diagnosis, treatment and prevention for patients and families affected by this disease.
Child ; Humans ; Autism Spectrum Disorder/therapy* ; Fragile X Mental Retardation Protein/genetics* ; Fragile X Syndrome/therapy* ; Intellectual Disability/genetics*

OBJECTIVE: To analyze the (CGG)n repeats of FMR1 gene among patients with unexplained mental retardation. METHODS: For 201 patients with unexplained mental retardation, the (CGG)n repeats of the FMR1 gene were analyzed by PCR and FragilEase RESULTS: For the 201 patients with unexplained mental retardation, 15 were identified with full mutations of the FMR1 gene. The prevalence of fragile X syndrome (FXS) in patients with unexplained mental retardation was determined as 7.5% (15/201). Prenatal diagnosis was provided for 6 pregnant women with pre- or full mutations. Analysis revealed that women with mental retardation and full FMR1 mutations exhibited a skewed XCI pattern with primary expression of the X chromosome carrying the mutant allele. CONCLUSION FXS has a high incidence among patients with unexplained mental retardation. Analysis of FMR1 gene (CGG)n repeats in patients with unexplained mental retardation can facilitate genetic counseling and prenatal diagnosis for their families. FMR1 gene (CGG)n repeats screening should be recommended for patients with unexplained mental retardation.
Female ; Fragile X Mental Retardation Protein/genetics* ; Fragile X Syndrome/genetics* ; Humans ; Intellectual Disability/genetics* ; Mutation ; Pregnancy ; Prenatal Diagnosis

Prader-Willi syndrome is characterized by such as infantile hypotonia, mental retardation hyperphagia with obesity and hypogonadism. We experienced one case of so called Prader-Willi syndrome associated with hypogonadotrophic hypogonadism, hypomentia, hyperphagia with obesity and cryptochism. Testicular biopsy revealed predominant Sertoli cells, decreased spermatogonia and edematous stromal tissue.
Biopsy ; Hyperphagia ; Hypogonadism ; Intellectual Disability ; Muscle Hypotonia ; Obesity ; Prader-Willi Syndrome* ; Sertoli Cells ; Spermatogonia

INTRODUCTION: The traditional cytogenetic analysis requires relatively long cell culture time, intensive labour and trained personnel. But, in clinical situations, rapid diagnosis of genetic disease is very important for urgent decision for future management. So we need more rapid and precise diagnostic tools for clinical genetic counselling. The fluorescence in situ hybridization (FISH) has been studied for detecting chromosomal aneuploidies because this method can get rapid and precise results of cytogenetic studies. OBJECTIVE: To evaluate the clinical utility of fluorescence in situ hybridization technique as a diagnostic tool of chromosomal anomaly. METHODS: Peripheral blood or gonadal tissue were obtained from the patients (n=63) clinically suspicious of genetic disease. Chorionic villi (n=6), amniotic fluid (n=9), and fetal cord blood (n=2) were obtained from 15 pregnancies undergoing fetal karyotyping at 9 to 30 weeks of gestation for prenatal genetic counselling. Karyotyping was performed by both traditional cytogenetics and FISH, using commercially available kits. After the procedures, the results of FISH were compared with the results of traditional cytogenetic studies. RESULTS: In a blind series of 17 samples all, including trisomy 21 (1 case), trisomy 18 (1 case), monosomyX (1 case), 47,XYY (1 case), and 47,XXY (1 case), were correctly identified. FISH results were correspondent with conventional karyotyping results in 7 patients with intersex except one case of suspicious of mosaicism. In nine children of Turner syndrome, the results of two methods were correspondent too. There was a fluorescent signal defect in band 15 q11-q13 in one of chromosome 15 in 18 children of 29 patients, clinically suspicious of Prader-Willi syndrome, with FISH method and only four patients were diagnosed as Prader-Willi syndrome with G-banding microscope. It was impossible to identify the defect in chromosome 15 q11-q13 in 10 (34%) children by both methods. Two children of 11 patients, clinically suspicious of Angelman syndrome, were diagnosed as Angelman syndrome with both method respectively. And four children were diagnosed as Angelman syndrome only with FISH method. In 5 cases, we cannot detect the defect in chromosome 15 q11-q13 with both methods. In four cases of Williams syndrome, the results of both methods were as follows; 1 case (25%): diagnosed as Williams syndrome by both methods; 2 cases (50%): diagnosed
Amniotic Fluid ; Aneuploidy ; Angelman Syndrome ; Cell Culture Techniques ; Child ; Chorionic Villi ; Chromosomes, Human, Pair 15 ; Cytogenetic Analysis ; Cytogenetics ; Diagnosis* ; Down Syndrome ; Female ; Fetal Blood ; Fluorescence* ; Gonads ; Humans ; In Situ Hybridization* ; Karyotyping ; Mosaicism ; Prader-Willi Syndrome ; Pregnancy ; Trisomy ; Turner Syndrome ; Williams Syndrome

Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is caused by deletion of chromosome 11p13, including the Wilms' tumor (WT1) and aniridia gene (PAX6) loci. Here, we report the first case of WAGR syndrome in Korea; the patient was a 2-year-old girl with bilateral aniridia from birth who presented with abdominal distention and mental retardation. Cytogenetically, she had deletion of chromosome 11p11.2-13. Bilateral Wilms' tumors were successfully treated by chemotherapy and surgery. She has been tumor-free for 19 months off chemotherapy with preserved renal function.
Aniridia ; Humans ; Intellectual Disability ; Korea ; Parturition ; Preschool Child ; WAGR Syndrome ; Wilms Tumor