The purpose of the present study was to assess the relationship between clinical characteristics of spinocerebellar ataxia type 6 (SCA6) and CAG repeat length.
Materials and methods: We examined clinical symptoms of 54 patients with SCA6. CAG repeat length was compared among subgroups divided by clinical manifestations.
Results: The major symptom was progressive cerebellar ataxia. Truncal or limb ataxia, dysarthria, and nystagmus were observed in more than 80% of the patients. In analysis of CAG repeat length in patients with different types of nystagmus, CAG repeat length was the longest when both upbeat and downbeat nystagmus existed (P < 0.01). In addition, CAG repeat length was longer when the initial symptom was ataxic gait and was shorter when the initial symptom was dysarthria or ocular symptom (P < 0.05).
Conclusion: Clinical features of SCA6 might be influenced by the length of abnormal CAG repeat.