RESUMEN
Objective To study the molecular genetic diagnosis and clinical characteristics of spinocerebellar ataxia type 6 (SCA6).Methods 43 patients with autosomal dominant SCA from 36 families and 38 sporadic SCA patients were enrolled in the study. SCA6 (CAG)n dynamic mutations were detected by polymerase chain reaction (PCR). Abnormal allele fragments were sequenced and repeated numbers were calculated. The clinical data of two cases with SCA6 were analyzed.Results CAG repeat of normal SCA6 allele ranged from 10 to 13. CAG repeat of abnormal SCA6 allele expanded to 25 in one familial patient and 24 in one sporadic patient in our study. The basic characteristics of these SCA6 patients were slowly progressive cerebellar ataxia, nystagmus and dysarthria.Conclusion Diagnosis of SCA6 can be confirmed by detection of abnormal CAG repeat expansion. There is no obvious difference of clinical features between SCA6 and other SCA subtypes.