脊髓小脑性共济失调1型一哈萨克族家系遗传学特征分析

The analysis of genetic characteristics of spinocerebellar ataxia type 1 in a Kazak family

目的探讨脊髓小脑性共济失调1型(spinocerebellar ataxia type 1,SCA1)一哈萨克族家系遗传学特征。方法应用聚合酶链反应、琼脂糖凝胶电泳、T载体连接克隆测序等技术对42例家系成员进行ATXN1基因CAG三核苷酸重复数目测定。对检测结果进行分析并与表型正常的家系成员和健康人对照。结果42例家系成员中SCA1基因突变者19例,5例已发病SCA1患者异常等位基因CAG重复数目为41~47次。家系内表型正常的23例成员SCA1等位基因CAG重复数目为17~30次。60名健康对照者SCA1等位基因CAG重复数目为12~30次。在正常等位基因中发现CAT结构的插入。结论哈萨克族SCA1家系是国内首次报告少数民族SCA1家系,CAG异常扩增数目在不同民族中存在差异。等位基因中CAT结构的插入更有利于基因的稳定性。

Objective To explore the genetic characteristics of the spinocerebellar ataxia type 1(SCA1)in a Kazakh family.Methods Genetic test(ATXN1 gene)of 42 family members were conducted by polymerase chain reaction,agarose gel electrophoresis and T vector ligand sequencing.Genetic test results were analyzed and comparison of phenotypes were made between family members and healthy people.Results Among the 42 family members,19 had the mutation of SCA1 gene,and the number of CAG repeats of the abnormal allele in 5 patients with SCA1 was 41 to 47,while the number of CAG repeats in the 23 members with normal phenotype in the family was 17 to 30.The number of the SCA1 allele CAG in 60 healthy controls were 12 to 30.Insertion of CAT structure found in normal alleles.Conclusion The Kazak SCA1 family is the first reported of SCA1 in ethnic minority families in China,and the abnormal length of CAG repeats varies among different ethnic groups.The insertion of the CAT structure in the allele tends to increase the stability of the gene.