脊髓小脑性共济失调一家系的基因诊断

Genetic diagnosis of a family with spinocerebellar ataxia

目的对1个常染色体显性遗传的脊髓小脑性共济失调(SCA)家系进行基因诊断。方法采用PCR技术,对一汉族SCA家系(包括3例患者及3位无症状成员)及50名正常对照者的SCA1～3基因进行检测,通过琼脂糖凝胶电泳和产物直接测序法计数等位基因内CAG三核苷酸重复次数。结果该家系中所有成员SCA1、SCA2基因CAG三核苷酸重复次数在正常范围;3例患者SCA3 CAG重复次数分别为67、68和66次,1位无症状成员为71次。结论该家系为SCA3,基因检测诊断出1例症状前患者。

Objective To genetic diagnosis in a family with autosomal dominant spinocerebellar ataxia（SCA）.Methods PCR technique was used to detect the SCA1-3 pathogenic genes on one Chinese Han SCA family（including 3 SCA patients and 3 asymptomatic members）and 50 healthy controls.The times of CAG trinucleotide duplicate was identified by agarose gel electrophoresis and product direct sequencing method.Results In the SCA family,the duplicate times of SCA1 and SCA2 CAG trinucleotide of all the members were in the normal range,but SCA3 CAG in 3 patients were 67,68 and 66 times,respectively;and one asymptomatic member was 71 times.Conclusions This family can be diagnosed as SCA3.One presymptomatic patient is diagnosed by genetic detection.