目的：探讨脊髓小脑性共济失调6型（SCA6）一家系中患者的临床、病理、分子生物学特点，并评价治疗效果。方法采集 SCA6家系临床资料，行基因测序。对其中3例进行肌肉活检，测定肌肉组织中过氧化物酶体增殖物激活受体辅激活因子1α（PGC-1α）的表达；给予治疗，应用共济失调等级量表（SARA）和临床总体印象量表（CGIS）评价临床治疗效果。结果该家系共9例患者（2例已死亡）首发症状均为小脑性共济失调，主要表现为进行性行走不稳和直线行走困难，并伴有构音障碍、水平眼震。4例行基因检测示 CAG 重复异常。2例肌肉病理结果示轻度肌源性损害病理改变，伴线粒体功能异常，1例示大致正常肌组织。3例肌肉组织中 PGC-1α的表达较正常对照组表达降低。治疗后患者临床症状明显改善。结论SCA6患者存在肌肉组织线粒体功能异常及PGC-1α表达降低，提示线粒体功能异常可能在 SCA 发病过程中起重要作用。给予保护线粒体功能治疗能明显改善患者的临床症状。“,”Objective To investigate the clinical,pathological,molecular biological features and the treatment outcome for a pedigree of spinocerebellar ataxia type 6(SCA 6).Methods Physical examinations and gene sequencing were performed.Muscular biopsies were performed in 3 patients.The expression of peroxisomeproliferators activatedreceptor-coactivator-1α(PGC-1α)in the myocyte was detected.Patients were treated with drugs,and the treatment outcome of 4 patients were measured with the scale for the assessment and rating of ataxia scores(SARA)and clinical global impressions scale(CGIS).Results The basic manifestations of the patients were slowly progressive cerebellar ataxia, mainly manifested unstable gait and difficulty in walking straight,and accompanied with nystagmus and dysarthria.nys-tagmus and dysarthria.An abnormal CAG repeats existed in the SCA6 gene.In muscle biopsies,2 patients showed mild muscle damage with mitochondrial dysfunction and 1 showed normal.But PGC-1αexpression decreased in all patients.The clinical symptoms of the patients were improved markedly.Conclusion Mitochondrial dysfunction and depression of PGC-1αexist in the muscle of SCA6 patients.These findings imply that impaired function of mitochondri-al may play a critical role in the process of SCA,and the treatment with mitochondrial protective agents can exert thera-peutic benefits.