• Clinical and Experimental Pediatrics
• /
• 제48권4호
• /
• pp.425-432
• /
• 2005

목 적 : 폴리글루타민 질환은 해당 발현단백질의 연속되는 글루타민 아미노산 서열이 신장되기 때문에 일어나는 질환군이다. 현 연구는 폴리글루타민 질환 형질전환 초파리 모델들이 환자들 에서와 유사한 장애를 나타내는지 확인하기 위해 수행되었다. 방 법 : 폴리글루타민 질환 (SCA3) 형질전환 초파리를 대상으로 벽을 기어오르는 운동 능력을 검사하였다. 또한 유전학적인 방법을 통해서 아폽토시스를 억제하는 bcl-2 유전자와 화학적 샤페론이 뇌신경의 퇴행에 어떤 영향을 미치는지 확인하였으며 향후의 연구를 위해 척수소뇌 운동실조증 타입 2 (SCA2) 질환을 발현하는 형질전환 초파리를 생산하였다. 결 과 : SCA3 형질전환 초파리에서 신장된 폴리글루타민 배열을 지니는 질환성 초파리의 경우 신경계에서 해당 단백질을 발현하였을 경우 전형적인 운동 능력 상실을 나타냈다. 아폽토시스를 억제하는 유전자인 bcl-2를 함께 발현했을 경우, 신장된 단백질의 유독한 영향을 약화시키지 못했지만, 화학적 샤페론인글리세롤의 경우 적어도 눈에서의 유독한 영향은 억제하는 것으로 보인다. 본 연구진에 의해 개발된 SCA2 형질전환 초파리의 경우 유해 단백질의 발현 정도가 낮아서 정확한 분석이 어려웠다. 결 론 : SCA3 형질전환 초파리는 환자들에서 발견되는 운동실조증을 보였다. 글리세롤과 같은 화학적 샤페론이 현재 치료가 전무한 이 종류의 질환군의 치료에 효과적일 것으로 사료된다.

• Journal of Genetic Medicine
• /
• 제4권1호
• /
• pp.22-37
• /
• 2007

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.

• Journal of Genetic Medicine
• /
• 제12권1호
• /
• pp.38-43
• /
• 2015

Purpose: Spinocerebellar ataxias (SCAs) are progressive neurodegenerative disorders with diverse modes of inheritance. There are several subtypes of SCAs. SCA 8, SCA 12, and SCA 17 are the less common forms of SCAs with limited information available on their epidemiological profiles in Korea. The purpose of this study was to investigate the prevalence of SCA8, SCA12, and SCA17 in Korea. Materials and Methods: Ninety-six unrelated Korean patients were enrolled and showed normal trinucleotide repeats through polymerase-chain reaction (PCR) for the genes ATXN1, ATXN2, ATXN3, CACNA1A, and ATXN7, which correspond to SCA1, SCA2, SCA3, SCA6, and SCA7, respectively. PCR products from patients were further analyzed by capillary electrophoresis using fluorescence labeled primers for the genes ATXN8OS, PPP2R2B, and TBP, which correspond to SCA8, SCA12, and SCA17. Results: Three patients had 104, 97, and 75 abnormal expanded repeats in the ATXN8OS gene, the causative gene for SCA8. None of the patients exhibited abnormal repeats in SCA12 and SCA17. Normal trinucleotide repeat ranges of the cohort in this study were estimated to be 17-34 copies (average, $24{\pm}4copies$) for SCA8, 7-18 copies (average, $13{\pm}3copies$) for SCA12, and 26-43 copies (average, $35{\pm}2copies$) for SCA17. Conclusion: This study demonstrated that SCA8, SCA12, and SCA17 are rare in Korean patients with SCA, and further genetic studies are warranted to enhance the mutation detection rate in the Korean SCA population.

• Molecules and Cells
• /
• 제19권1호
• /
• pp.23-30
• /
• 2005

Spinocerebellar ataxia type 1 (SCA1) is an autosomal-dominant neurodegenerative disorder caused by expansion of the polyglutamine tract in the SCA1 gene product, ataxin-1. Using d2EGFP, a short-lived enhanced green fluorescent protein, we investigated whether polyglutamine-expanded ataxin-1 affects the function of the proteasome, a cellular multicatalytic protease that degrades most misfolded proteins and regulatory proteins. In Western blot analysis and immunofluorescence experiments, d2EGFP was less degraded in HEK 293T cells transfected with ataxin-1(82Q) than in cells transfected with lacZ or empty vector controls. To test whether the stability of the d2EGFP protein was due to aggregation of ataxin-1, we constructed a plasmid carrying $ataxin-1-{\Delta}114$, lacking the self-association region (SAR), and examined degradation of the d2EGFP. Both the level of $ataxin-1-{\Delta}114$ aggregates and the amount of d2EGFP were drastically reduced in cells containing $ataxin-1-{\Delta}114$. Furthermore, d2EGFP localization experiments showed that polyglutamine-expanded ataxin-1 inhibited the general function of the proteasome activity. Taken together, these results demonstrate that polyglutamine-expanded ataxin-1 decreases the activity of the proteasome, implying that a disturbance in the ubiquitin-proteasome pathway is directly involved in the development of spinocerebellar ataxia type1.

• Journal of Genetic Medicine
• /
• 제11권2호
• /
• pp.69-73
• /
• 2014

Purpose: Spinocerebellar ataxia (SCA) is a genetically heterogeneous disease for which more than 30 subtypes have been identified. However, 5 subtypes, SCA1, SCA2, SCA3, SCA6, and SCA7, account for more than 60% of cases. In this study, we report the distribution of these 5 subtypes in Korean patients. Materials and Methods: Six hundred and thirty-eight unrelated patients with a presumptive diagnosis of SCA were included in this study. Trinucleotide (CAG) repeat number (TNR) repeat number was determined using fluorescently labeled primers and fragment analysis. Results: A total of 128 unrelated patients (20.1% of all individuals tested) tested positive for SCA subtypes, including SCA1 (5 patients, 3.9% of those testing positive), SCA2 (38 patients, 29.7%), SCA3 (30 patients, 23.4%), SCA6 (39 patients, 30.5%), and SCA7 (16 patients, 12.5%). The mean copy number of pathogenic TNR alleles was $45{\pm}8.5$ for SCA1, $42{\pm}3.1$ for SCA2, $72{\pm}5.4$ for SCA3, $23{\pm}1.5$ for SCA6, and $50{\pm}11.4$ for SCA7. TNR copy number was inversely correlated with onset age in SCA2, SCA6, and SCA7. Conclusion: SCA2, SCA3, and SCA6 are common SCA subtypes in Korean patients and could be screened as a first-line test. Expanded pathogenic allele size was associated with early onset age.

• Journal of Genetic Medicine
• /
• 제15권2호
• /
• pp.110-114
• /
• 2018

Ataxia-telangiectasia (AT; OMIM 208900) is a rare autosomal recessive inherited progressive neurodegenerative disorder, with onset in early childhood. AT is caused by homozygous or compound heterozygous mutations in ATM (OMIM 607585) on chromosome 11q22. The average prevalence of the disease is estimated at 1 of 100,000 children worldwide. The prevalence of AT in the Republic of Korea is suggested to be extremely low, with only a few cases genetically confirmed thus far. Herein, we report a 5-year-old Korean boy with clinical features such as progressive gait and truncal ataxia, both ankle spasticity, dysarthria, and mild intellectual disability. The patient was identified as a compound heterozygote with two novel genetic variants: a paternally derived c.5288_5289insGA p.(Tyr1763*) nonsense variant and a maternally derived c.8363A>C p.(His2788Pro) missense variant, as revealed by next-generation sequencing and confirmed by Sanger sequencing. Based on claims data from the Health Insurance Review and Assessment Service Republic of Korea, we calculated the prevalence of AT in the Republic of Korea to be about 0.9 per million individuals, which is similar to the worldwide average. Therefore, we suggest that multi-gene panel sequencing including ATM should be considered early diagnosis.

• Molecules and Cells
• /
• 제24권3호
• /
• pp.338-342
• /
• 2007

Spinocerebellar ataxias (SCAs) are caused by expansion of (CAG)n triplet repeats. These repeats occur as polymorphic forms in general population; however, beyond a threshold size they become pathogenic. The sizes and distributions of repeats at the SCA1, SCA2, SCA3, SCA7 and DRPLA loci were assessed by molecular analysis of 124 unrelated ataxia patients and 44 controls, and the association of larger normal (LN) alleles with disease prevalence was evaluated. Triplet repeat expansions in the disease range were detected in 8% (10/124) of the cases, with the majority having expansion at the SCA1 locus. Normal allele ranges in the cohort studied were similar to the Caucasian and North Indian populations but differed from the Korean and Japanese populations at various loci. The percentage of individuals with LN alleles at the SCA1 and SCA2 loci was higher than reported in Indians, Japanese and Caucasians. LN alleles showed a good correlation with the incidence of SCA1, indicating that SCA1 is the most prevalent ataxia in our population. The majority of cases with clinical symptoms of SCA could not be diagnosed by established CAG repeat criteria, suggesting that there may be an alternative basis for disease pathogenesis: (i) Repeats lower than the normal range may also result in abnormal phenotypes (ii) LN alleles at different loci in the same individual may contribute to symptoms (iii) Exogenous factors may play a role in triggering disease symptoms in individuals with LN alleles (iv) Triplet repeats may reach the disease range in the brain but not in the blood.

• Journal of Genetic Medicine
• /
• 제4권1호
• /
• pp.84-87
• /
• 2007

척수소뇌성 실조증3는 신경세포의 손상으로 인해 생기는 질병으로 염색체14q32.1지역에 반복적인 CAG 삼염기 서열이 증가하면서 일어나는 것으로 알려져 있다. 본 증례는 척수소뇌성 실조증3으로 진단을 받은 부부에서 자연 임신한 태아를 산전진단한 경우로서 형광으로 포식된 표지자를 이용하여 CAG 지역을 증폭하여 빠르고 정확하게 반복수를 확인하는 방법을 이용하였다. 남편의 경우 CAG반복을 넘는 69개의 반복과 정상인 27개의 반복된 유전자를 갖고 있는 것으로 확인하였으며, 산모의 경우 정상인 26과 32개의 반복된 유전자를 갖고 있는 것으로 확인하였다. 태아는 부계의 27과 모계의 26개를 갖는 정상 유전자를 물려 받은 것으로 확인되어 건강한 아기를 분만하였다. 형광을 이용한 진단방법은 방사능을 사용하는 방법에 비해 안전하고 빠른 진단을 할 수 있으며 시료 채취 후 5-6시간 안에 정확하게 결과를 확인할 수 있는 방법이라 생각된다.

• 대한생식의학회:학술대회논문집
• /
• 대한생식의학회 2007년도 제52차 춘계학술대회 초록집
• /
• pp.132-132
• /
• 2007

• 한국콘텐츠학회논문지
• /
• 제18권11호
• /
• pp.634-642
• /
• 2018

소뇌운동실조증(SCA)은 유전성, 진행성 신경장애로 SCA 환자는 소뇌위축으로 인한 실조형 마비말장애를 보인다. 본 연구는 집중 말운동치료를 통해 SCA환자의 진행성 실조형 마비말장애의 개선의 유무를 확인하고, 개선이 있는 경우, 치료전후의 변화의 정도를 보고하고자 한다. 55세의 SCA 여성 환자를 대상으로 말운동 기능 개선을 위한 SPEAK $OUT!^{(R)}$ 치료프로그램을 시행 후, 큰 효과크기 수준에서 MPT와 과제별 음량의 개선이 관찰되었고, 음도의 경우 적은 효과크기의 변화를 보였다. 그러나 음도의 폭은 큰 효과크기의 변화를 보였다. 음질은 jitter, shimmer, HNR 모두에서 큰 효과크기 수준에서 긍정적 개선을 보였고, 모음면적도 넓어졌는데 이때 F1의 변화가 두드러졌다. 또한 심도 수준의 VHI점수는 치료 후 경도 수준으로 낮아졌다. 집중 말운동치료 프로그램인 SPEAK $OUT!^{(R)}$의 시행을 통해 SCA 환자의 음량, 음도, 음도의 폭, 음질, 모음면적의 증가를 관찰하였고, 음성장애에 관한 주관적 인식의 변화도 긍정적으로 감소하였다. 기초연구로서의 본 결과를 바탕으로 SCA환자의 진행성 실조형 마비말장애 개선을 위한 SPEAK $OUT!^{(R)}$에 대한 좀 더 체계적인 검증을 위한 후속 연구가 필요하다.