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Rapid prenatal diagnosis of spinocerebellar ataxia type 3 by using fluorescent PCR.

Do Jin KIM ; So Yeon PARK ; Mi Jin KIM ; Moon Hee LEE ; Sung Han SHIM ; Hyun Mee RYU

Journal of Genetic Medicine.2007;4(1):84-87.

Spinocerebellar Ataxia Type 3 (SCA3) is a rare autosomal dominative disorder in which one of the neurodegenerative disorders is caused by a CAG repeat expansion on chromosome 14q32.1. The age at onset of disease is related to the size of the expanded CAG repeat. We present the prenatal diagnosis of SCA3 in a woman whose husband was known to carry an unstable CAG repeat expansion in the MJD gene. The diagnosis was made using PCR with a fluorescent probe for an expanded MJD allele. The normal ranges of (CAG)n of SCA3 are 14~38 repeats. The husband, who had a family history of SCA3, has an expanded allele of 69 CAG repeats with a normal allele of 27 repeats. His wife had two normal alleles with 26 and 32 CAG repeats. The fetus had two normal alleles with 26 and 27 CAG repeats; consequently, the baby was healthy. We report a case of prenatal diagnosis of SCA3 using a fluorescent PCR which is rapid and accurate.
Female ; Humans

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Prenatal diagnosis of a de novo ring chromosome 11.

Ju Yeon PARK ; Moon Hee LEE ; Bom Yi LEE ; Yeon Woo LEE ; Hyun Mee RYU ; So Yeon PARK

Journal of Genetic Medicine.2007;4(1):80-83.

A 36-year-old pregnant woman was referred for amniocentesis at 19.5 weeks gestation because of advanced maternal age and evidence of increased risk for Edward syndrome in the maternal serum screening test. Cytogenetic analysis of the cultured amniotic fluid cells revealed mosaicism for ring chromosome 11: 46,XX,r(11)[65]/45,XX,-11[16]/46,XX[34]. Parental karyotypes were normal. A targeted ultrasound showed intrauterine growth restriction (IUGR). Cordocentesis was performed to characterize the ring chromosome and to rule out tissue specific mosaicism. Karyotype was confirmed as 46,XX,r(11) (p15.5q24.2)[229]/45,XX,-11[15]. And a few new form of ring were detected in this culture. The deletion of subtelomeric regions in the ring chromosome were detected by fluorescent in situ hybridization (FISH). The pregnancy was terminated. The fetal autopsy showed a growth-retarded female fetus with rocker bottom feet. We report a case of prenatally detected a de novo ring chromosome 11.
Pregnancy ; Female ; Humans

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AGL gene mutation and clinical features in Korean patients with glycogen storage disease type III.

Jung Min KO ; Gu Hwan KIM ; Han Wook YOO

Journal of Genetic Medicine.2007;4(1):72-79.

PURPOSE: Glycogen storage disease type III (GSD-III) is a rare autosomal recessive disorder of glycogen metabolism. The affected enzyme, amylo-1,6-glucosidase, 4-alpha-glucanotransferase (AGL, glycogen debranching enzyme), is responsible for the debranching of the glycogen molecule during catabolism. The disease shows clinical and biochemical heterogeneity, reflecting genotype-phenotype heterogeneity among different patients. In this study, we aim at analyzing mutations of the AGL gene in three unrelated Korean GSD-III patients, and characterizing their clinical and laboratory findings. METHODS: We characterized the clinical features of three unrelated Korean GSD-III patients by biochemical, histological and imaging studies. The 35 exons and part of exon-intron boundaries of AGL were analyzed by direct sequencing using genomic DNA extracted from the peripheral leukocytes of patients. RESULTS: Diverse clinical features were observed in these patients including hepatomegaly (all patients), seizures (patient 2), growth failure (patients 1 and 2), hyperlipidemia (patients 1 and 3), raised transaminase and creatine kinase concentrations (all patients), and mild cardiomyopathy (patient 2). Liver transplantation was performed in patient 2 due to progressive hepatic fibrosis. Administration of uncooked corn starch maintained normoglycemia and improved biochemical and growth profiles. DNA sequence analysis revealed mutations in 5 out of 6 alleles. Patient 1 was a compound heterozygote of c.1282 G>A (p.R428K) and c.1306delA (p.S603PfsX6), patient 2 had c.1510_1511insT (p.Y504LfsX10), and patient 3 had c.3416 T>C (p.L1139P) and c.1735+1 G>T (p.Y538_R578delfsX4) mutations. Apart from the p.R428K mutation, the 4 other substitutions identified were novel. CONCLUSION: GSD-III patients display variable phenotypic characteristics resembling those of GSD-Ia. Molecular defects in the AGL gene of Korean GSD-III patients are genetically heterogeneous.

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Rapid prenatal diagnosis of Down syndrome and Edward syndrome by fluorescence In situ hybridization:Clinical experience with 309 cases.

Jin Hee KANG ; Sook Hwan LEE ; Sang Hee PARK ; Ji Hyun PARK ; Ji Youn KIM ; Won Bo HAN ; In Hyun KIM ; Sang Won PARK ; Jin Beum JANG ; Kyoung Jin LEE ; Hee Jin PARK ; Hye Sun JUN ; Kyung Ju LEE ; Joong Sik SHIN ; Dong Hyun CHA

Journal of Genetic Medicine.2007;4(1):64-71.

PURPOSE: The purpose of this study was to evaluate the clinical utility of rapid detection of Down syndrome and Edward syndrome by Interphase Fluorescence in Situ Hybridization (FISH) analysis METHODS: A retrospective study in 309 cases of amniotic fluid samples, analysed by interphase FISH with DNA probes specific to chromosome 18 and 21, was performed. All FISH results were compared with conventional cytogenetic karyotypings. RESULTS: The results were considered as informative and they were obtained within 48 hrs. A case of Down syndrome and a case of Edward syndrome were diagnosed by FISH and confirmed by subsequent cytogenetic analysis. In 12 cases with normal FISH results, the cytogenetic analysis showed a case of partial trisomy 22, three cases of sex chromosomal aneuploidy, two cases of mosaicism, two cases of microdeletion, and four cases of structural rearrangement. CONCLUSION: FISH is a rapid and effective diagnostic method, which can be used as an adjunctive test to cytogenetic analysis, for prenatal identification of chromosome aneuploidies. For the more genome- wide screening with variety of probes, the technique of FISH is both expensive and labor-intensive.

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A cost-benefit analysis on tandem mass spectrometry of inherited metabolic diseases in Korea.

Hyoung Ock RYU ; Dong Hwan LEE ; Tae Youn CHOI ; Hye Ran YOON

Journal of Genetic Medicine.2007;4(1):53-63.

PURPOSE: Tandem mass spectrometry (MS/MS) is effective screening test for inherited metabolic diseases. In this study, we estimate potential costs and benefits of using tandem mass spectrometry (MS/MS) to screen newborns for inherited metabolic diseases (phenylketonuria, BH4 deficiency, citrullinemia, maple syrup urine disease, propionic aciduria, isovaleric aciduria, glutaric aciduria type 1, LCHAD deficiency) in Korea. METHODS: From April 2001 to March 2004, 79,179 newborns were screened for amino acid disorders, organic acid disorders, and fatty acid oxidative disorders. Twenty-eight newborns were diagnosed with one of the metabolic disorder and the collective estimated prevalence amounted to 1 in 2,800 with a sensitivity of 97.67%, a specificity of 99.28%, a recall rate of 0.05%, and a positive preditive value of 6.38%. We calculated and compared the total costs in case when neonatal screening on phenylketonuria, BH4 deficiency, citrullinemia, maple syrup urine disease, propionic aciduria, isovaleric aciduria, glutaric aciduria type 1, LCHAD deficiency is implemented, and when not. RESULTS: If the neonatal screening on phenylketonuria, BH4 deficiency, citrullinemia, maple syrup urine disease, propionic aciduria, isovaleric aciduria, glutaric aciduria type 1, LCHAD deficiency is implemented, total benefits far exceed costs at a ratio of 1.40:1. CONCLUSION: Although, this study only concerns the monetary aspects of the neonatal screening, tandem mass spcetrometry for neonatal screening is cost-effective compared with not screening. The study appears to support the introduction of tandem mass spectrometry into a Korea neonatal screening programme for inherited metabolic diseases.
Infant, Newborn ; Humans

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Determination of plasma C16-C24 globotriaosylceramide (Gb3) isoforms by tandem mass spectrometry for diagnosis of Fabry disease.

Hye Ran YOON ; Kyunghee CHO ; Han Wook YOO ; Jin Ho CHOI ; Dong Hwan LEE ; Kate ZHANG ; Joan KEUTZER

Journal of Genetic Medicine.2007;4(1):45-52.

PURPOSE: A simple, rapid, and highly sensitive analytical method for Gb3 in plasma was developed without labor-extensive pre-treatment by electrospray ionization MS/MS (ESI-MS/MS). Measurement of globotriaosylceramide (Gb3, ceramide trihexoside) in plasma has clinical importance for monitoring after enzyme replacement therapy in Fabry disease patients. The disease is an X-linked lipid storage disorder that results from a deficiency of the enzyme ??-galactosidase A (alpha-Gal A). The lack of alpha-Gal A causes an intracellular accumulation of glycosphingolipids, mainly Gb3. METHODS: Only simple 50-fold dilution of plasma is necessary for the extraction and isolation of Gb3 in plasma. Gb3 in diluted plasma was dissolved in dioxane containing C17:0 Gb3 as an internal standard. After centrifugation it was directly injected and analyzed through guard column by in combination with multiple reaction monitoring mode of ESI-MS/MS. RESULTS: Eight isoforms of Gb3 were completely resolved from plasma matrix. C16:0 Gb3 occupied 50% of total Gb3 as a major component in plasma. Linear relationship for Gb3 isoforms was found in the range of 0.001-1.0 microgram/mL. The limit of detection (S/N=3) was 0.001 microgram/mL and limit of quantification was 0.01 microgram/mL for C16:0 Gb3 with acceptable precision and accuracy. Correlation coefficient of calibration curves for 8 Gb3 isoforms ranged from 0.9678 to 0.9982. CONCLUSION: This quantitative method developed could be useful for rapid and sensitive 1st line Fabry disease screening, monitoring and/or diagnostic tool for Fabry disease.

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Identification of novel mutations of the ATP7A gene and prenatal diagnosis of Menkes disease by mutation analysis.

Jin Ho CHOI ; Gu Hwan KIM ; Han Wook YOO

Journal of Genetic Medicine.2007;4(1):38-44.

PURPOSE: Menkes disease is an X-linked recessively inherited disorder caused by the mutation of the ATP7A gene encoding copper-transporting P-type ATPase. The phenotypic features are progressive neurological degeneration, mental retardation, loose skin, and vascular complications. Early diagnosis and treatment are very important for the prognosis of Menkes disease. Here, we describe novel mutations of the ATP7A gene and prenatal diagnosis by mutation analysis. METHODS: Five unrelated Korean Menkes patients were included in this study. They presented with depigmented wool-like hair, progressive neurologic deterioration, and hypotonia in infancy. Serum copper and ceruloplasmin levels were decreased. Brain magnetic resonance imaging revealed tortuous intracranial vessels. Mutation analysis has been carried out using cDNA from cultured skin fibroblasts or genomic DNA from peripheral leukocytes. Prenatal diagnosis was performed in two cases using chorionic villi samples or amniocytes. RESULTS: Four novel mutations have been identified from four different families; c.3511+1G Female ; Humans

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Spinocerebellar ataxia 7 (SCA7).

Seon Yong JEONG ; Seok Hun JANG ; Hyon J KIM

Journal of Genetic Medicine.2007;4(1):22-37.

The autosomal dominant spinocerebellar ataxias (SCAs) are a group of neurodegenerative diseases, clinically and genetically heterogeneous, characterized by degeneration of spinocerebellar pathways with variable involvement of other neural systems. At present, 27 distinct genetic forms of SCAs are known: SCA1-8, SCA10-21, SCA23, SCA25-28, DRPLA (dentatorubral-pallidoluysian atrophy), and 16q-liked ADCA (autosomal dominant cerebellar ataxia). Epidemiological data about the prevalence of SCAs are restricted to a few studies of isolated geographical regions, and most do not reflect the real occurrence of the disease. In general a prevalence of about 0.3-2 cases per 100,000 people is assumed. As SCA are highly heterogeneous, the prevalence of specific subtypes varies between different ethnic and continental populations. Most recent data suggest that SCA3 is the commonest subtype worldwide; SCA1, SCA2, SCA6, SCA7, and SCA8 have a prevalence of over 2%, and the remaining SCAs are thought to be rare (prevalence <1%). In this review, we highlight and discuss the SCA7. The hallmark of SCA7 is the association of hereditary ataxia and visual loss caused by pigmentary macular degeneration. Visual failure is progressive, bilateral and symmetrical, and leads irreversibly to blindness. This association represents a distinct disease entity classified as autosomal dominant cerebellar ataxia (ADCA) type II by Harding. The disease affectsprimarily the cerebellum and the retina by the moderate to severe neuronal loss and gliosis, but also many other central nervous system structures as the disease progresses. SCA7 is caused by expansion of an unstable trinucleotide CAG repeat in the ATXN7 gene encoding a polyglutamine (polyQ) tract in the corresponding protein, ataxin-7. Normal ATXN7 alleles contain 4-35 CAG repeats, whereas pathological alleles contain from 36->450 CAG repeats. Immunoblott analysis demonstrated that ataxin-7 is widely expressed but that expression levels vary among tissues. Instability of expanded repeats is more pronounced in SCA7 than in other SCA subtypes and can cause substantial lowering of age at onset in successive generations termed 'anticipation' so that children may become diseased even before their parents develop symptoms. The strong anticipation in SCA7 and the rarity of contractions should have led to its extinction within a few generations. There is no specific drug therapy for this neurodegenerative disorder. Currently, therapy remains purely symptomatic. Cellular models and SCA7 transgenic mice have been generated which constitute valuable resources for studying the disease mechanism. Understanding the pathogenetic mechanisms of neurodegeneration in SCAs should lead to the identification of potential therapeutic targets and ultimately facilitate drug discovery. Here we summarize the clinical, pathological, and genetic aspects of SCA7, and review the current understanding of the pathogenesis of this disorder. Further, we also review the potential therapeutic strategies that are currently being explored in polyglutamine diseases.
Child ; Male ; Female ; Humans ; Mice ; Animals

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Hereditary cancer and genetic counseling.

Seung Yong JEONG

Journal of Genetic Medicine.2007;4(1):15-21.

Hereditary syndromes cause approximately 5 to 10% of overall cancer cases. Cancer related with genetic syndromes are found elsewhere, including stomach, breast, colorectum, ovary, brain and so on. Because hereditary cancers are due to germline mutations, these patients have unique clinical features distinct from sporadic cancer. Generally these features include (i) early age-of onset of cancer, (ii) frequent association with synchronous or metachronous tumors, (iii) frequent bilateral involvement in paired organs (iv) frequent association with other site tumors or characteristic clinical manifestation specific to each genetic syndrome. Due to these differences, the management strategy for patients with hereditary cancer is quite different from that for sporadic cancer. Additionally, there are important screening and surveillance implications for family members. Genetic counselling is prerequisite to these families for risk assessment by pedigree analysis, and guidance to clinical or genetic testing. The genes responsible for these syndromes has recently identified, as a result, genetic testing has become important determining factor in clinical decisions.

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Genetic counselling in prenatal genetic testing.

Doyeong HWANG

Journal of Genetic Medicine.2007;4(1):6-14.

No abstract available.

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