Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominantly inherited disorder characterized by cerebellar ataxia, dysarthria and nystagmus. The molecular background for the disorder is a CAG repeat expansion in t...Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominantly inherited disorder characterized by cerebellar ataxia, dysarthria and nystagmus. The molecular background for the disorder is a CAG repeat expansion in the CACNA1A gene located on chromosome 19. The size of SCA6 expanded alleles is usually stable, and variation in repeat size over successive generations is rare. We report a Danish family with one case of SCA6 resembling a sporadic case of spinocerebellar ataxia. Analysis of the CACNA1A gene showed meiotic CAG repeat instability in the transmission from a 70- year-old woman with no subjective symptoms to her symptomatic son. The CAG repeat size expanded from 22 repeats in the mother to 23 repeats in the proband. This case demonstrates maternal repeat instability and clinical anticipation in a family with SCA6.展开更多
文摘Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominantly inherited disorder characterized by cerebellar ataxia, dysarthria and nystagmus. The molecular background for the disorder is a CAG repeat expansion in the CACNA1A gene located on chromosome 19. The size of SCA6 expanded alleles is usually stable, and variation in repeat size over successive generations is rare. We report a Danish family with one case of SCA6 resembling a sporadic case of spinocerebellar ataxia. Analysis of the CACNA1A gene showed meiotic CAG repeat instability in the transmission from a 70- year-old woman with no subjective symptoms to her symptomatic son. The CAG repeat size expanded from 22 repeats in the mother to 23 repeats in the proband. This case demonstrates maternal repeat instability and clinical anticipation in a family with SCA6.
文摘一、概述：脊髓小脑性共济失调（SCAs）是遗传性共济失调（hemditaryataxia，HA）的主要类型。由于其病理损害的主要部位是脊髓、脑干、小脑，故又将遗传性共济失调称为脊髓小脑性共济失调（spinocerebellar ataxias，SCAs）。Harding在1993根据临床表现、遗传方式和生化改变对SCAs进行了临床分型，其主要包括常染色体显性小脑性共济失润（autosom al dominant cerebellar ataxia，ADCA）和常染色体隐性小脑性共济失调（autmom aI recessive cerebellar ataxia，ARCA）两大类别。
