Abstract:

Objective To investigate the causative mutations in a spinocerebellar ataxia（SCA） pedigree and the types of the SCA pedigree,and to provide a reference for genetic counseling. Methods Genomic DNA was extracted from peripheral blood of 5 subjects,including 3 SCA patients,in the SCA pedigree. Totally,9 sets of primers were designed for the polymerase chain reaction（PCR） amplification of 9 fragments,including SCA1,SCA2,SCA3,SCA6,SCA7,SCA8,SCA12,SCA17 and dentatorubral-pallidoluysian atrophy（DRPLA） gene,respectively. Causative mutations were screened and were validated by Sanger sequencing. Results Repeat lengths of 76,78 and 75,above that of 12-44 CAG triplets reported in healthy people from literatures,were observed in the 3 patients from the SCA3 pedigree. Another member carrying a repeat length of 74 in the pedigree was diagnosed as a causative mutation of the SCA3 gene carrier by Sanger sequencing. Conclusions PCR amplification combined with Sanger sequencing is a convenient and efficient method to identify causative mutations for SCA gene,which can be used for carrier screening and prenatal diagnosis.

Key words: Spinocerebellar ataxia, Polymerase chain reaction, Sanger sequencing, Genetic diagnosis