宁夏地区回、汉族脊髓小脑共济失调家系SCA3/MJD基因突变研究

目的通过对宁夏地区临床诊断为脊髓小脑共济失调的3个家系(2个汉族家系、1个回族家系)进行SCA3/MJD基因检测,探讨脊髓小脑共济失调的发病机制与临床特点,以为临床应用提供依据。方法对3家系受试者进行神经系统检查和系谱调查,部分行头部MRI和肌电图检查,以及SCA3/MJD基因胞嘧啶-腺嘌呤-鸟嘌呤(CAG)重复数目检测。结果3家系中共计8例脊髓小脑共济失调患者(汉族家系1中6例、汉族家系2中1例和回族家系中1例),符合常染色体显性遗传特点,以共济失调与构音障碍为主要表现,其次为眼外肌麻痹、眼球震颤、慢眼动、锥体束征等。其中汉族家系1和回族家系明确诊断为SCA3/MJD家系,两家系中7例患者(汉族家系1中6例、回族家系中1例)及2例临床表型正常亲属(两家系中各1例)检测出SCA3/MJD异常等位基因,其CAG重复数目为66～81次。汉族家系2中1例患者及汉族家系1中4例临床表型正常亲属SCA3/MJD基因CAG重复数目为20～33次。正常等位基因与异常等位基因CAG重复数目差异有统计学意义(t=5.309,P=0.000)。结论宁夏地区回、汉族脊髓小脑共济失调患者中存在SCA3/MJD基因型,基因检测分析有利于明确诊断脊髓小脑共济失调且能够检出症状前患者。

Study on SCA3/MJDgene mutatiion of Hui and Han nationality families with spinocerebellar ataxias in Ningxia region

Objective To explore the pathogenesis and clinical features of spinocerebellar ataxias(SCAs) for the evidence of clinical application by SCA3 / MJD gene mutation analysis of 3 families(2 Han na-tionality families and one Hui nationality family) clinically diagnosed as SCAs in Ningxia region.Methods Nervous systemic physical examination and pedigree analysis were perfomed on the subjects in 3 families.Brain magnetic resonance imaging(MRI) scanning,electromyograpy,and determination of SCA3 / MJD gene cytosine-adenine-guanine(CAG) repeat were performed on part of the subjects.Results There were 8 SCAs patients(6 from Han nationality family 1,one from Han nationality family 2 and one from Hui nationality fam-ily) in 3 families with autosomal dominant inheritance feature.The main presentations were ataxia and dysarthria in association with at least one of the following signs:external ophthalmoplegia,nystagmus,eye slow movement,pyramidal sign,etc.Among them,Han nationality family 1 and Hui nationality family were con-firmed as SCA3 / MJD subtype.Abnormal SCA3 / MJD alleles were detected in 7 patients(6 from Han nation-ality family 1 and one from Hui nationality family) and 2 relatives with normal clinical phenotype(one in each family),and there were 66-81 CAG repeats.In one patient from Han nationality family 2 and 4 relatives from Han nationality family 1,normal SCA3 / MJD allele CAG repeats were 20-33.The difference of CAG repeat between normal and abnormal alleles was significant(t = 5.309,P = 0.000).Conclusion SCA3 / MJD geno-type is found in all Hui and Han nationality patients with spinocerebellar ataxias in Ningxia region.Genemutation analysis is benefit for accurate diagnosis of spinocerebellar ataxias and detection of presymptomatic patients.