Progression of ataxia in patients with Machado-Joseph disease.

Although ataxia is the most distressing manifestation of Machado-Joseph disease (MJD), little is known about its natural history. Therefore, we prospectively followed a cohort of patients with MJD for 13 months to characterize the progression of ataxia and identify its contributory factors. The international cooperative ataxia rating scale (ICARS) was used to estimate severity of ataxia at baseline and at follow-up. Thirty-four patients were enrolled in the study, 22 of whom were men. Mean age at onset of the disease was 34.7 years and length of expanded CAG repeat was 66. Mean ICARS scores at baseline was 37.6 and at follow-up was 42.7 (P < 0.001). Multivariate analysis did not find significant association of progression of disease and age at disease onset, length of expanded (CAG), or duration of disease.