الملخص
<p><b>OBJECTIVE</b>To study the clinical features and gene mutation analysis in Machado-Joseph disease of spinocerebellar ataxia type 3 in littoral of Zhejiang.</p><p><b>METHODS</b>Clinical manifestation and brain MRI data 18 patients with SCA in family were analyzed. The gene mutations of 18 patients and 10 family numbers without abnormal presentation, and 12 healthy persons of controls.</p><p><b>RESULTS</b>The gene mutations of 18 patients is SCA3/MJD, and 2 asymptomatic SCA3/MJD had been detected in SCA family. Normal alleles of SCA3/MJD have CAG repeats ranging from 14 to 27, patients from 67 to 82, asymptomatic and carrier SCA3/MJD from 28 to 45. The main features of 18 patients included gait ataxia, ambiguity in speech and action clumsiness. Brain MRI showed remarkable atrophy on cerebellum and brain stem.</p><p><b>CONCLUSION</b>CAG expansions were related to SCA3/MJD. The clinical manifestations are ataxia and dysarthria. The detection of repeated times CAG can provide an effective way for the genetic and asymptomatic diagnosis.</p>