Identification of novel susceptibility genes associated with bone density and osteoporosis in Korean women

Purpose@#Osteoporosis is a common calcium and metabolic skeletal disease which is characterized by decreased bone mass, microarchitectural deterioration of bone tissue and impaired bone strength, thereby leading to enhanced risk of bone fragility.In this study, we aimed to identify novel genes for susceptibility to osteoporosis and/or bone density. @*Materials and Methods@#To identify differentially expressed genes (DEGs) between control and osteoporosis-induced cells, annealing control primer-based differential display reverse-transcription polymerase chain reaction (RT-PCR) was carried out in pre-osteoblast MC3T3-E1 cells. Expression levels of the identified DEGs were evaluated by quantitative RT-PCR. Association studies for the quantitative bone density analysis and osteoporosis case-control analysis of single nucleotide polymorphism (SNPs) were performed in Korean women (3,570 subjects) from the Korean Association REsource (KARE) study cohort. @*Results@#Comparison analysis of expression levels of the identified DEGs by quantitative RT-PCR found seven genes, Anxa6, Col5a1, Col6a2, Eno1, Myof, Nfib, and Scara5, that showed significantly different expression between the dexamethasontreated and untreated MC3T3-E1 cells and between the ovariectomized osteoporosis-induced mice and sham mice. Association studies revealed that there was a significant association between the SNPs in the five genes, ANXA6, COL5A1, ENO1, MYOF, and SCARA5, and bone density and/or osteoporosis. @*Conclusion@#Using a whole-genome comparative expression analysis, gene expression evaluation analysis, and association analysis, we found five genes that were significantly associated with bone density and/or osteoporosis. Notably, the association P-values of the SNPs in the ANXA6 and COL5A1 genes were below the Bonferroni-corrected significance level.

Loss of Heterozygosity at Chromosome 16q Is a Negative Prognostic Factorin Korean Pediatric Patients with Favorable Histology Wilms Tumor:A Report of the Korean Pediatric Hematology Oncology Group (K-PHOG) / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Loss of heterozygosity (LOH) at chromosomes 1p and 16q is a poor prognostic factor infavorable histology Wilms tumor (FHWT). This study investigated the prevalence of LOH at1p and 16q and evaluated its prognostic value in Korean children with FHWT. @*Materials and Methods@#We analyzed 101 FHWT patients who were diagnosed between 1996 and 2016 in KoreanSociety of Pediatric Hematology Oncology Group hospitals. Using paraffin-embedded kidneytissue samples sent from each center, we reviewed LOH at 1p and 16q in each patient andassessed the prognostic value of LOH status for clinical parameters affecting event-freesurvival (EFS). @*Results@#Of the 101 patients, 12 (11.9%) experienced recurrence; the 3-year EFS was 87.6%. LOHat 1p or 16q was detected in 19 patients (18.8%), with five having LOH at both 1q and 16q.The frequency of LOH at 1p was higher among younger patients (p=0.049), but there wasno difference in LOH prevalence according to tumor stage. In the multivariate analysis, LOHat 16q was a significant negative prognostic factor affecting EFS (3-year EFS, 73.7% vs.91.1%; hazard ratio, 3.95; p=0.037), whereas LOH at 1p was not (p=0.786). @*Conclusion@#LOH at 16q was a significant negative prognostic factor affecting outcome in Korean pediatricFHWT patients. Due to the small sample size of this study, large-scale multicenter trialsare warranted to investigate the prognostic value of LOH at 1p and 16q in Korean childrenwith FHWT.

Evaluation of the VE1 Antibody in Thyroid Cytology Using Ex Vivo Papillary Thyroid Carcinoma Specimens

BACKGROUND: Recently, VE1, a monoclonal antibody against the BRAFV600E mutant protein, has been investigated in terms of its detection of the BRAFV600E mutation. Although VE1 immunostaining and molecular methods used to assess papillary thyroid carcinoma in surgical specimens are in good agreement, evaluation of VE1 in thyroid cytology samples is rarely performed, and its diagnostic value in cytology has not been well established. In present study, we explored VE1 immunoexpression in cytology samples from ex vivo papillary thyroid carcinoma specimens in order to minimize limitations of low cellularity and sampling/targeting errors originated from thyroid fineneedle aspiration and compared our results with those obtained using the corresponding papillary thyroid carcinoma tissues. METHODS: The VE1 antibody was evaluated in 21 cases of thyroid cytology obtained directly from ex vivo thyroid specimens. VE1 immunostaining was performed using liquid-based cytology, and the results were compared with those obtained using the corresponding tissues. RESULTS: Of 21 cases, 19 classic papillary thyroid carcinomas had BRAFV600E mutations, whereas two follicular variants expressed wild-type BRAF. VE1 immunoexpression varied according to specimen type. In detection of the BRAFV600E mutation, VE1 immunostaining of the surgical specimen exhibited 100% sensitivity and 100% specificity, whereas VE1 immunostaining of the cytology specimen exhibited only 94.7% sensitivity and 0% specificity. CONCLUSIONS: Our data suggest that VE1 immunostaining of a cytology specimen is less specific than that of a surgical specimen for detection of the BRAFV600E mutation, and that VE1 immunostaining of a cytology specimen should be further evaluated and optimized for clinical use.

A Korean case of neurofibromatosis type 1 with an exonic splicing enhancer site mutation

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease characterized by neurological, cutaneous, and ophthalmological manifestations. A 33-year-old woman with typical symptoms of NF1 visited Ajou University Hospital. Screening of the whole-messenger RNA region of NF1 at the complementary DNA level by polymerase chain reaction-direct sequencing confirmed the presence of an NF1 mutation at the genomic level. The mutation analysis revealed an in-frame skipping of exon 46 (c.6757_6858del) caused by a point mutation (c. 6792C>A) in exon 46. In this report, we have described the first Korean case of a proband with NF1 that carries an allele with an exon 46 deletion caused by an exonic splicing enhancer site mutation, leading to the skipping of the whole of exon 46 (c.6757_6858del).

Ocular Abnormality of Korean Patients with Molecular Genetically Confirmed Gaucher Disease

PURPOSE: To investigate the ophthalmologic manifestations of Korean patients with Gaucher disease. METHODS: Clinical records of 5 patients who were referred to the pediatric ophthalmology clinic of Seoul National University Bundang Hospital after diagnosis of Gaucher disease at the genetics clinic of Ajou University Hospital between 2007 and 2008 were retrospectively reviewed. RESULTS: Five patients with type 3 Gaucher disease had hepatosplenomegaly and oculomotor apraxia, and 4 patients had growth and developmental delay. The most commonly detected genetic mutation was L444P. In addition, P201H, F2131, R257Q, and D315E+Rec 1b were identified. Five patients had oculomotor apraxia and limitation of abduction, and 4 patients had esotropia. One of the 4 patients who showed combined limitation of abduction, oculomotor apraxia, and esotropia, yet did not have growth and developmental delay. CONCLUSIONS: Most of the patients who were referred for ocular motor abnormalities with Gaucher disease showed a limitation of abduction, oculomotor apraxia, and esotropia. In patients with a limitation of abduction, oculomotor apraxia, and esotropia, Gaucher disease should be considered. Ophthalmologic examination is essential for subtyping and prognosing Gaucher disease.

An Unusual Presentation of Diabetic Ketoacidosis in Familial Hajdu-Cheney Syndrome: A Case Report

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.

Correlation Between Unidentified Bright Objects on Brain Magnetic Resonance Imaging (MRI) and Cerebral Glucose Metabolism in Patients with Neurofibromatosis Type 1

PURPOSE: Neurofibromatosis type 1 (NF1), which is caused by mutations of the NF1 gene, is the most frequent single gene disorder to affect the nervous system. Unidentified bright objects (UBOs) are commonly observed on brain magnetic resonance imaging (MRI) in patients with NF1. However, their clinical and pathologic significance is not well understood. The purpose of this study was to investigate the correlation between UBOs and cerebral glucose metabolism measured by 18F-2-Fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) in Korean patients with NF1. MATERIALS AND METHODS: Medical records of 75 patients (34 males and 41 females) with NF1 who underwent brain MRI and PET between 2005 and 2011 were evaluated retrospectively. Clinical data including demographics, neurological symptoms, and brain MRI and PET findings, were reviewed. RESULTS: UBOs were detected in the brain MRI scans of 31 patients (41%). The region most frequently affected by UBOs was the basal ganglia. The most frequent brain PET finding was thalamic glucose hypometabolism (45/75, 60%). Of the 31 patients with UBOs, 26 had thalamic glucose hypometabolism on brain PET, but the other 5 had normal brain PET findings. Conversely, of the 45 patients with thalamic glucose hypometabolism on brain PET, 26 showed UBOs on their brain MRI scans, but 19 had normal findings on brain MRI scans. CONCLUSION: UBOs on brain MRI scans and thalamic glucose hypometabolism on PET appear to be 2 distinctive features of NF1 rather than correlated symptoms. Because the clinical significance of these abnormal imaging findings remains unclear, a longitudinal follow-up study of changes in clinical manifestations and imaging findings is necessary.

Correlation Between Unidentified Bright Objects on Brain Magnetic Resonance Imaging (MRI) and Cerebral Glucose Metabolism in Patients with Neurofibromatosis Type 1

PURPOSE: Neurofibromatosis type 1 (NF1), which is caused by mutations of the NF1 gene, is the most frequent single gene disorder to affect the nervous system. Unidentified bright objects (UBOs) are commonly observed on brain magnetic resonance imaging (MRI) in patients with NF1. However, their clinical and pathologic significance is not well understood. The purpose of this study was to investigate the correlation between UBOs and cerebral glucose metabolism measured by 18F-2-Fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) in Korean patients with NF1. MATERIALS AND METHODS: Medical records of 75 patients (34 males and 41 females) with NF1 who underwent brain MRI and PET between 2005 and 2011 were evaluated retrospectively. Clinical data including demographics, neurological symptoms, and brain MRI and PET findings, were reviewed. RESULTS: UBOs were detected in the brain MRI scans of 31 patients (41%). The region most frequently affected by UBOs was the basal ganglia. The most frequent brain PET finding was thalamic glucose hypometabolism (45/75, 60%). Of the 31 patients with UBOs, 26 had thalamic glucose hypometabolism on brain PET, but the other 5 had normal brain PET findings. Conversely, of the 45 patients with thalamic glucose hypometabolism on brain PET, 26 showed UBOs on their brain MRI scans, but 19 had normal findings on brain MRI scans. CONCLUSION: UBOs on brain MRI scans and thalamic glucose hypometabolism on PET appear to be 2 distinctive features of NF1 rather than correlated symptoms. Because the clinical significance of these abnormal imaging findings remains unclear, a longitudinal follow-up study of changes in clinical manifestations and imaging findings is necessary.

Two Children with Saethre-Chotzen Syndrome Confirmed by the TWIST1 Gene Analysis

Saethre-Chotzen syndrome is an autosomal dominant craniosynostosis syndrome, usually involving unior bilateral coronal synostosis and mild limb deformities, and is induced by loss-of-function mutations of the TWIST1 gene. Other clinical features of this syndrome include ptosis, low-set ears, hearing loss, hypertelorism, broad great toes, clinodactyly, and syndactyly. The authors of the present study report 2 children with clinical features of Saethre-Chotzen syndrome who showed mutations in the TWIST1 gene, and is the first molecular genetic confirmation of Saethre-Chotzen syndrome in Korea. The molecular genetic testing of the TWIST1 gene for patients with coronal synostoses is important to confirm the diagnosis and to provide adequate genetic counseling.

A case of donor-derived granulocytic sarcoma after allogeneic hematopoietic stem cell transplantation / 대한혈액학회지

The occurrence of granulocytic sarcoma as a pattern of relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is rare. In this paper, we report a rare case of acute myeloid leukemia (AML) relapsed as a granulocytic sarcoma of the donor type. The patient was diagnosed as having AML and underwent an allo-HSCT from his matched sibling donor. Fifty-seven months after allo-HSCT, he developed granulocytic sarcomas of duodenum, jejunum, and left sterno-cleido-mastoid muscle. The bone marrow was normal with 100% donor chimerism. A Y chromosome PCR was performed on the patient's duodenum specimen as well as bone marrow aspirate in order to check the patient-origin cells. The duodenal specimen was found to contain 41.2% SRY-positive cells (from the donor). Repeat endoscopy on day 2 of chemotherapy showed that the granulocytic sarcoma had shrunk dramatically. The patient died of sepsis during the nadir state 35 days after starting salvage chemotherapy.

Loss of Y Chromosome in the Malignant Peripheral Nerve Sheet Tumor of a Patient with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is one of the most commonly inherited autosomal dominant disorders. In order to determine whether genomic alterations and/or chromosomal aberrations involved in the malignant progression of NF1 were present in a Korean patient with NF1, molecular and cytogenetic analyses were performed on the pathologically normal, benign, and malignant tissues and primary cells cultured from those tissues of the patient. The comparative genomic hybridization (CGH) array revealed a Y chromosome loss in the malignant peripheral nerve sheet tumor (MPNST) tissue. G-banding analysis of 50 metaphase cells showed normal chromosomal patterns in the histopathologically normal and benign cultured cells, but a mosaic Y chromosome loss in the malignant cells. The final karyotype for the malignant cells from MPNST tissue was 45,X,-Y[28]/46,XY[22]. The data suggest that the somatic Y chromosome loss may be involved in the transformation of benign tumors to MPNSTs.

De Novo Pericentric Inversion of Chromosome 9 in Congenital Anomaly

PURPOSE: The pericentric inversion of chromosome 9 is one of the most common structural balanced chromosomal variations and has been found in both normal populations and patients with various abnormal phenotypes and diseases. The aim of this study was to re-evaluate the clinical impact of inv(9)(p11q13). MATERIALS AND METHODS: We studied the karyotypes of 431 neonates with congenital anomalies at the Pediatric Clinic in Ajou University Hospital between 2004 and 2008 and retrospectively reviewed their clinical data. RESULTS: Chromosomal aberrations were detected in 60 patients (13.9%). The most common type of structural abnormality was inv(9)(p11q13), found in eight patients. Clinical investigation revealed that all eight cases with inv(9)(p11q13) had various congenital anomalies including: polydactyly, club foot, microtia, deafness, asymmetric face, giant Meckel's diverticulum, duodenal diaphragm, small bowel malrotation, pulmonary stenosis, cardiomyopathy, arrhythmia, and intrauterine growth restriction. The cytogenetic analysis of parents showed that all of the cases were de novo heterozygous inv(9)(p11q13). CONCLUSION: Since our results indicate that the incidence of inv(9)(p11q13) in patients with congenital anomalies was not significantly different from the normal population, inv(9)(p11q13) does not appear to be pathogenic with regard to the congenital anomalies. Some other, to date unknown, causes of the anomalies remain to be identified.

A Study of Guidelines for Genetic Counseling in Preimplantation Genetic Diagnosis (PGD)

PURPOSE: Preimplantation genetic diagnosis (PGD), also known as embryo screening, is a pre-pregnancy technique used to identify genetic defects in embryos created through in vitro fertilization. PGD is considered a means of prenatal diagnosis of genetic abnormalities. PGD is used when one or both genetic parents has a known genetic abnormality; testing is performed on an embryo to determine if it also carries the genetic abnormality. The main advantage of PGD is the avoidance of selective pregnancy termination as it imparts a high likelihood that the baby will be free of the disease under consideration. The application of PGD to genetic practices, reproductive medicine, and genetic counseling is becoming the key component of fertility practice because of the need to develop a custom PGD design for each couple. MATERIALS AND METHODS: In this study, a survey on the contents of genetic counseling in PGD was carried out via direct contact or e-mail with the patients and specialists who had experienced PGD during the three months from February to April 2010. RESULTS: A total of 91 persons including 60 patients, 49 of whom had a chromosomal disorder and 11 of whom had a single gene disorder, and 31 PGD specialists responded to the survey. Analysis of the survey results revealed that all respondents were well aware of the importance of genetic counseling in all steps of PGD including planning, operation, and follow-up. The patient group responded that the possibility of unexpected results (51.7%), genetic risk assessment and recurrence risk (46.7%), the reproduction options (46.7%), the procedure and limitation of PGD (43.3%) and the information of PGD technology (35.0%) should be included as a genetic counseling information. In detail, 51.7% of patients wanted to be counseled for the possibility of unexpected results and the recurrence risk, while 46.7% wanted to know their reproduction options (46.7%). Approximately 96.7% of specialists replied that a non-M.D. genetic counselor is necessary for effective and systematic genetic counseling in PGD because it is difficult for physicians to offer satisfying information to patients due to lack of counseling time and specific knowledge of the disorders. CONCLUSIONS: The information from the survey provides important insight into the overall present situation of genetic counseling for PGD in Korea. The survey results demonstrated that there is a general awareness that genetic counseling is essential for PGD, suggesting that appropriate genetic counseling may play a important role in the success of PGD. The establishment of genetic counseling guidelines for PGD may contribute to better planning and management strategies for PGD.

Hereditary Palmoplantar Keratoderma and Deafness Resulting from Genetic Mutation of Connexin 26

Gap junctions, which mediate rapid intercellular communication, consist of connexins, small transmembrane proteins that belong to a large family of proteins found throughout the species. Mutations in the GJB2 gene, encoding Connexin 26, can cause nonsyndromic autosomal recessive or dominant hearing loss with or without skin manifestations. A 3-yr-old Korean female and her mother presented to our clinic with diffuse hyperkeratosis of the palms and soles (May 3, 2007). Skin biopsies from the soles of both patients demonstrated histopathological evidence of palmoplantar keratoderma. The patient and a number of her maternal family members also had congenital hearing loss. The combination of congenital hearing loss and palmoplantar keratoderma, inherited as an autosomal dominant trait, led us to test for a mutation in the GJB2 gene in both patients. The results showed the R75W mutation of the GJB2 gene in both. In conclusion, the simultaneous occurrence of a GJB2 mutation in a mother and daughter suggests that R75W mutation cause autosomal dominant hearing loss presenting with palmoplantar keratoderma. To the best of our knowledge, this is the first report of a GJB2 mutation associated with syndromic autosomal dominant hearing loss and palmoplantar keratoderma in a Korean family.

Retraction

No abstract available.

A Case of Birt-Hogg-Dube Syndrome

Birt-Hogg-Dube syndrome (BHDS) is an autosomal dominant genodermatosis characterized by cutaneous hair follicle tumors (fibrofolliculoma or trichodiscoma), pulmonary cysts, and increased risk of renal neoplasia. The genetic alteration for BHDS has been mapped to chromosome 17p12q11, and the gene in this region has been cloned and believed to be responsible for the BHDS. Mutations in the BHD gene (also known as FLCN) have been described in the patients with BHDS. We present a case of a 30-yr-old Korean woman with multiple mildly pruritic papules on her face and neck area. The patient had several firm, flesh-colored, dome-shaped, papular lesions measuring between 2 to 5 mm. Except for a history of pneumothorax her medical records were not remarkable. Mutation analysis of the BHD gene was performed, and a novel deletion mutation (p.F519LfsX17 [c.1557delT]) causing truncation of the gene product, folliculin, was found in the exon 14. The actual incidence of BHDS is unknown, but it is most likely underdiagnosed. So it is imperative that doctors recognize the skin lesions of BHDS and institute proper screening to detect other manifestations of the disease. Here, we report a case of BHDS with a novel mutation, which is the first report in Korea.

Multiple Endocrine Neoplasia Type 1 with Multiple Leiomyomas Linked to a Novel Mutation in the MEN1 Gene

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominantly inherited syndrome. MEN1 is characterized by the presence of functioning and nonfunctioning tumors or hyperplasia of the pituitary gland, parathyroid glands, and pancreatic islet cells. In addition, MEN1 carriers can have adrenal or thyroid tumors and non-endocrine tumors, such as lipomas, angiofibromas, and leiomyomas. Although leiomyoma is not a major component of MEN1, it is thought to occur more frequently than expected. However, there has been no report of a case of MEN1 with leiomyoma in Korea so far. This report describes a patient with multiple leiomyomas in MEN1. A 50-year-old woman was referred for further evaluation of elevated calcium levels and osteoporosis. Biochemical abnormalities included hypercalcemia with elevated parathyroid hormone. There was hyperprolactinemia with pituitary microadenoma in sella MRI. An abdominal MRI demonstrated adrenal nodules and leiomyomas in the bladder and uterus. Endoscopic ultrasonography demonstrated esophageal leiomyoma and pancreatic islet cell tumor. A subtotal parathyroidectomy with thymectomy was performed. Sequencing of the MEN1 gene in this patient revealed a novel missense mutation (D350V, exon 7). This is the first case of MEN1 accompanied with multiple leiomyomas, parathyroid adenoma, pituitary adenoma, pancreatic tumor, and adrenal tumor.

Molecular diagnosis of fragile X syndrome in a female child

PURPOSE: Fragile X syndrome (FXS) is the most common heritable cause of cognitive impairment. FXS is caused by hyperexpansion and hypermethylation of a polymorphic CGG trinucleotide repeat in the 5' untranslated region of the fragile X mental retadation-1(FMR1) gene. Combination of Southern blotting and simple polymerase chain reaction(PCR) amplification of the FMR1 repeat region is commonly used for diagnosis in females. To give a definite diagnosis in a female child suspected of having FXS, we carried out the molecular diagnostic test for FXS using the recently developed Abbott Molecular Fragile X PCR Kit. METHODS: The PCR amplification of the FMR1 repeat region was performed using the Abbott Mdecular Fragile X PCR Kit. The amplified products were analyzed by size-separate analysis on 1.5% agarose gels and by DNA fragment analysis using Gene scan. RESULTS: Agarose gel and Gene scan analyses of PCR products of the FMR1 repeat region showed that the patient had two heterozygous alleles with a normal 30 repeats and full mutation of >200 repeats whereas her mother had two heterozygous alleles with the normal 30 repeats and premutation of 108 repeats, suggesting that the premutation of 108 repeats in her mother may have led to the full mutation of >200 repeats in the patient. CONCLUSION: We diagnosed FXS in a female patient using a simplified molecular diagnostic test. This commercially available diagnostic test for FXS, based on PCR, may be a suitable alternative or complement method to Southern blot analysis and PCR analysis and/or methylation specific(MS)-PCR analysis for the molecular diagnosis of FXS in both males and females.

Controversial issues in the legal restriction for prenatal genetic testing in Korea

More than 6,000 rare disorders including genetic diseases have been reported. Of them, 1,500 diseases (1,211 for clinical diagnosis and 289 for research only) are technically possible for genetic testing. In Korea, since 2005, only 63 genetic diseases is permitted for prenatal genetic testing by the "Bioethics and Biosafety Law". The article 25 in the law prescribes 63 genetic diseases without clear indication for its selection and inclusion criteria. In EU, USA, and other foreign countries, however, there is no provision in the statute on prenatal genetic testing; it is not restricted by a law. Recently, a woman (Mrs. L, 38y) who is a carrier for Menkes disease made an appeal to a government for an amendment of the "Bioethics and Biosafety Law" prohibiting the prenatal diagnosis of her pregnancy at risk for Menkes disease. Menkes disease (MNK) is an X-linked recessive disorder characterized by neurodegeneration, connective tissue defects and hair abnormalities, and no effective treatment is available yet. The prevalence rate of MNK is one in about 250,000 live births. Menkes syndrome patients fail to absorb copper from the gastrointestinal tract in quantities adequate for meeting nutritional needs. These needs seem particularly acute during the initial 12 month of life, when the velocity of brain growth and motor neurodevelopment. Most of pts. die around 3yrs. of age. Mrs. L had a boy with Menkes disease who died at 2y.o. in 2001. Subsequent pregnancy in 2003, she was able to have prenatal genetic testing for mutation of the Menkes (ATP7A) gene and delivered a healthy baby boy. Now, She is pregnant again and wants to have prenatal diagnosis. however, this time, she was not allowed to have any more because Menkes disease is not included in 63 genetic diseases permitted by the law for prenatal genetic testing, in spite of the fact that she is a Menkes disease carrier and her pregnancy is at risk to have an affected baby. This case shows the practical problem of the legal restriction for prenatal genetic testing in Korea. In this study, we report a arguable case and discuss the controversial issues in the legal restriction for prenatal genetic testing in Korea.

Spinocerebellar ataxia 7 (SCA7)

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 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.