Neuromyelitis optica spectrum disorder in a patient with spinocerebellar ataxia type 6

@#Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant, late-onset, slowly progressive cerebellar ataxia due to a pathological CAG repeat expansion in CACNA1A. Inflammation may be involved in the pathogenesis and progression of the trinucleotide repeat expansion disorder. We report a rare case of a 59-year-old woman with SCA6 who developed neuromyelitis optica spectrum disorder (NMOSD). In our case, this combination is coincidental but suggests that an inflammatory response to an unstable CAG repeat may contribute to NMOSD pathogenesis

Genetic Screening for Spinocerebellar Ataxia Genes in a Japanese Single-Hospital Cohort

OBJECTIVE: Diagnosis of sporadic cerebellar ataxia is a challenge for neurologists. A wide range of potential causes exist, including chronic alcohol use, multiple system atrophy of cerebellar type (MSA-C), and sporadic late cortical cerebellar atrophy. Recently, an autosomal-dominant spinocerebellar ataxia (SCA) mutation was identified in a cohort of patients with non-MSA-C sporadic cerebellar ataxia. The aim of this study is to genetically screen genes involved in SCA in a Japanese single-hospital cohort. METHODS: Over an 8-year period, 140 patients with cerebellar ataxia were observed. There were 109 patients with sporadic cerebellar ataxia (no family history for at least four generations, 73 patients with MSA-C, and 36 patients with non-MSA-C sporadic cerebellar ataxia) and 31 patients with familial cerebellar ataxia. We performed gene analysis comprising SCA1, 2, 3, 6, 7, 8, 12, 17, 31, and dentatorubro-pallidoluysian atrophy (DRPLA) in 28 of 31 non-MSA-C sporadic patients who requested the test. Familial patients served as a control. RESULTS: Gene abnormalities were found in 57% of non-MSA-C sporadic cerebellar ataxia cases. Among patients with sporadic cerebellar ataxia, abnormalities in SCA6 were the most common (36%), followed by abnormalities in SCA1 (7.1%), SCA2 (3.6%), SCA3 (3.6%), SCA8 (3.6%), and DRPLA (3.6%). In contrast, gene abnormalities were found in 75% of familial cerebellar ataxia cases, with abnormalities in SCA6 being the most common (29%). For sporadic versus familial cases for those with SCA6 abnormalities, the age of onset was older (69 years vs. 59 years, respectively), and CAG repeat length was shorter (23 vs. 25, respectively) in the former than in the latter (not statistically significant). CONCLUSION: Autosomal-dominant mutations in SCA genes, particularly in SCA6, are not rare in sporadic cerebellar ataxia. The reason for the frequency of mutations in SCA6 remains unclear; however, the reason may reflect a higher age at onset and variable penetrance of SCA6 mutations.

A Case of Spinocerebellar Ataxia Type 6 Presenting Downbeat Nystagmus Alone

No abstract available.

Spinocerebellar Ataxia Type 6 in Two Korean Families

BACKGROUND: Spinocerebellar ataxia 6 (SCA6) is an autosomal dominant spinocerebellar degeneration and caused by the expansion of the polymorphic CAG repeat in the human alpha 1A voltage-dependent calcium channel subunit gene. In this study, we report the clinical and molecular genetic characteristics of SCA6 in 2 Korean families. We further describe that SCA6 and Episodic ataxia type 2 are simultaneously developed in same family showing no intergenerational changes of CAG repeat numbers. METHODS: Seventeen members of one family and nine of the other received detailed neurological examination and history taking at least one occasion. After the screening test, molecular diagnostic test by using Zhuchenko's method were performed in 13 patients in one family and 3 in the other, respectively. RESULTS: Normal range of CAG repeat in 92 normal individuals was 8 to 17. In this study, the numbers of CAG repeat in one family was 26 and in another was 23. There were no intergenerational differences in the numbers of CAG repeat. Despite the same number of CAG repeat, the clinical anticipation were found. Only one showed episodic ataxia clinically. CONCLUSIONS: Comparing with other types of SCA, the SCA6 had several remarkable characteristics: 1) very small CAG expansions (21-27 repeats) lead to clinical symptoms and the repeat numbers are relatively stable, 2) clinical anticipation is observed despite the relatively stable repeat on intergenerational transmission. The finidngs that an EA2 and a SCA6 exist in a same family may be suggest that two disease are the same disorder with a high phenotypic variablity.

Analysis of the clinical features and genetic mutation of spinocerebellar ataxia type 6 from Chinese kindreds / 临床神经病学杂志

Objective To study the clinical features and genetic mutation frequency of spinocerebellar ataxia (SCA) type 6 from Chinese kindreds. Methods The SCA6 (CAG)n trinucleotide repeat mutations were detected using polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis (PAGE) techniques in 330 patients with autosomal dominant SCA from 160 kindreds and 77 sporadic SCA patients, and the abnormal alleles fragments were sequenced by ABI377 DNA sequencing machine. The clinical features were assessed and cranial MRI examinations were performed in these patients.Results 6 patients from 4 SCA6 Chinese kindreds had abnormal SCA6 alleles with CAG repeat expanded to 25 and 26, respectively, of which 2.5% was about the positive rate, while CAG repeat of normal SCA6 allele ranged from 5 to 17. The basic characteristics of SCA6 patients were slowly progressive cerebellar ataxia and purely cerebellar atrophy.Conclusion SCA6 is one seldom subtype of SCA in Chinese patients with its characteristics both in clinic and imaging in contrast to other subtypes.