The Distribution Characteristics Of CAG Repeat In The CACNA1A Gene Of The Chinese Population And It's Application In Molecular Diagnosis Of SCA6

ObjectivesTo investigate distribution characteristics of CAG repeat in the CACNA1A gene of Chinese Han population and its application in molecular diagnosis of spinocerebellar ataxia type 6 (SCA6).MethodsThe trinucleotide repeats of CAG were detected via polymerase chain reaction (PCR) in two steps, denaturing polyacrylamide gel electrophoresis (DPAGE) and DNA sequencing in 300 normal individuals and 109 unrelated SCA patients.Results1.The number of CAG repeats ranged from 3 to 18 and 13 was most common in 300 normal individuals.2.One SCA6 patient with 24 CAG repeats was identified from 109 SCA patients.3.This patient's mother and elder brother were SCA6 patients two. They all showed slowly progressive cerebellar ataxia, dysarthria, nystagmus, minor impairment in vibration sensation and proprioceptive sensation in clinical manifestation with obviously anticipation.Conclusions1.SCA6 is rare in the Chinese Population.2.Mutation analysis of the CACNA1A gene is helpful for clinical diagnosis of SCA6.3.PCR in two steps increases the efficiency of molecular diagnosis in SCA6.