Pure Cerebellar Ataxia Presenting in the SCA 1

순수 소뇌실조증의 임상 양상으로 SCA 1의 과도한 CAG 반복서열을 보인 유전성 소뇌실조증 가족 1례

SCA 1 is an autosomal dominant disorder. The phenotypic manifestations of SCA 1 are not specific, and thus, the diagnosis of SCA 1 rests on molecular genetic testing. The number of CAG repeats ranges from 6-44 in normal alleles and from 39-81 repeats in disease-causing alleles(chromosomal locus 6p22-23). The main clinical features of SCA 1 are ataxia, dysarthria, ophthalmoparesis, extrapyramidal signs without retinal degeneration. A 24-year-old woman with suspected family history presented with progressive cerebellar ataxia, dysarthria, ptosis, titubation and general weakness. Brain MRI revealed a moderate cerebellar atrophy. A genomic polymerase chain reaction(PCR) analysis showed 66 repeats at the SCA 1 locus.