No abstract available.
Mass Screening*

No abstract available.
Mass Screening*

No abstract available.

No abstract available.
Flow Cytometry* ; Microscopy*

No abstract available.
Flow Cytometry* ; Microscopy*

Ring chromosome 21 causes a multitude of phenotypes, ranging from severe abnormalities to normal. The proposed mechanism of ring formation, breakage of both short and long arms of a chromosome with subsequent end to end fusion, remains unproven. We encountered a 4-year-old boy who presented developmental delay, microcephaly, micrognathia, hypertelorism, low-set ears, mild optic nerve hypoplasia, cleft lip and palate, scoliosis and left foot valgus, but normal brain MRI. Chromosome study from peripheral blood showed 46,XY, r(21)(p11.2q22.1) karyotype. The authors report the first case of ring chromosome 21 in Korea with a review of the literature.
Arm ; Brain ; Child, Preschool ; Cleft Lip ; Ear ; Foot ; Humans ; Hypertelorism ; Karyotype ; Korea ; Magnetic Resonance Imaging ; Male ; Microcephaly ; Optic Nerve ; Palate ; Phenotype ; Ring Chromosomes* ; Scoliosis

No abstract available.
Blood Donors* ; Chungcheongnam-do* ; Humans

Chromosomal microarray analysis (CMA) enables the genome-wide detection of submicroscopic chromosomal imbalances with greater precision and accuracy. In most other countries, CMA is now a commonly used clinical diagnostic test, replacing conventional cytogenetics or targeted detection such as FISH or PCR-based methods. Recently, some consensus statements have proposed utilization of CMA as a first-line test in patients with multiple congenital anomalies not specific to a well-delineated genetic syndrome, developmental delay/intellectual disability, or autism spectrum disorders. CMA can be used as an adjunct to conventional cytogenetics to identify chromosomal abnormalities observed in G-banding analysis in constitutional or acquired cases, leading to a more accurate and comprehensive assessment of chromosomal aberrations. Although CMA has distinct advantages, there are several limitations, including its inability to detect balanced chromosomal rearrangements and low-level mosaicism, its interpretation of copy number variants of uncertain clinical significance, and significantly higher costs. For these reasons, CMA is not currently a replacement for conventional cytogenetics in prenatal diagnosis. In clinical applications of CMA, knowledge and experience based on genetics and cytogenetics are required for data analysis and interpretation, and appropriate follow-up with genetic counseling is recommended.
Child ; Autism Spectrum Disorder ; Chromosome Aberrations ; Coat Protein Complex I ; Consensus ; Cytogenetics ; Diagnostic Tests, Routine ; Genetic Counseling ; Genomic Structural Variation ; Humans ; Microarray Analysis ; Mosaicism ; Prenatal Diagnosis ; Statistics as Topic

PURPOSE: In general, genetic disorders have the numerical or structural abnormalities of chromosome. There are clinically two different disorders, Prader-Willi syndrome(PWS) and Angelman syndrome(AS), which have the deletion of specific region of 15 chromosome originated from father or mother by genetic imprinting phenomenon. We reported the results of genetic study including DNA methylation analysis and fluorescence in situ hybridization(FISH), in addition to clinical findings. METHODS: We studied 20 patients of PWS and AS diagnosed in pediatric department of Asan Medical Center from 1992 Feb. to 2001 Apr., retrospectively. We analyzed the clinical manifestations of the disorders and performed cytogenetic studies from the peripheral blood. And we the methylation pattern and FISH, using the probe for single nucleotide ribonucleoprotein N(SNRPN) locus within the Prader-Willi/Angelman region (15q11-q13). RESULTS: Among 16 patients of PWS, the age at initial visit was from 3 days to 12 years and the male to female ratio was 1.67:1. Seven patients had the history of intrauterine growth retardation or fetal distress. The chief complaints at initial presentation were classified on age. Under 3 years(n=10), there were hypotonia(4), development delay (3), feeding difficulties(2), and tachycardia(1). Above 3 years(n=6), we found short stature(2), respiratory difficulty(1), seizure(1), obesity(1), and undescended testes(1). DNA methylation study showed the methylation of 15 chromosome originated from paternal chromosome and the microdeletion by FISH was detected in all 12 among 12 patients (100%). In AS(n=4), the sex ratio(M:F) was 3:1 and age at presentation was from 15 months to 6 years. The important sign was severe developmental delay in all patients, combined with mental retardation in one case. Other clinical manifestations were depigmentation of skin and hair(4), prognathism(3), seizure(3), frequent laughing(2), undescended testes(1), hypotonia(1), and hyperactivity(1). FISH study was performed and showed the microdeletion of 15 chromosome in all 4 patients. CONCLUSION: We studied the clinically two different disorders, PWS and AS, with the deletion of same region of 15 chromosome and reported the results of the clinical and genetic analysis based on clinical findings and DNA analysis and FISH study, respectively.
Angelman Syndrome* ; Chungcheongnam-do ; Cytogenetics ; DNA ; DNA Methylation ; Fathers ; Female ; Fetal Distress ; Fetal Growth Retardation ; Fluorescence ; Genomic Imprinting ; Humans ; Intellectual Disability ; Male ; Methylation ; Mothers ; Prader-Willi Syndrome* ; Retrospective Studies ; Ribonucleoproteins ; Skin ; snRNP Core Proteins