Analysis of the gene mutation and clinical characteristic of hereditary spinocerebellar ataxia type 7 / 临床神经病学杂志

ABSTRACT

Objective To study the gene mutation and clinical characteristic of hereditary spinocerebellar ataxia type 7 (SCA7).Methods The SCA7 (CAG) trinucleotide repeat mutations were detected by polymerase chain reaction(PCR) and polyacrylamide gel electrophoresis technique in 24 patients with autosomal dominant SCA from 15 families, 20 sporadic SCA patients and 41 normal persons from the same family and 30 healthy persons from different family,the abnormal allele fragments were sequenced by ABI 373 DNA sequencing machine.Results 24 patients with SCA had CAG repeat numbers of SCA 7 allele from 9~18.Normal alleles of SCA 7 had CAG repeat number from 9 to 19. One sporadic SCA patient had one abnormal SCA 7 allele with the CAG repeat expanded to 63 repeats, being confirmed by DNA sequencing.Conclusion CAG expansions were pathogenic cause of SCA 7. The technique of gene mutation detection could provide an effective way for the prediction of asymptomatic and genetic counseling,which was a basis for gene typing.