Clinical Characteristics Of Spinocerebellar Ataxia Type2in Chinese Han Population And Analysis Of ATXN2Gene Mutation

Background:Spinocerebellar ataxia type2(SCA2) is a subtype of autosomal dominant spinocerebellar ataxia (AD-SCA). Abnormal CAG trinucleotide repeat tract in exon1of ATXN2gene have been found to be the genetic cause of SCA2in1996, which is located on chromosome12q23-24. Coordination disorder is the major clinical manifestation of SCA2.Objective:Through screening the genotype of SCA patients and PD patients, we can find the carriers of ATXN2gene mutation, then analyse the characteristics of clinical feathers and CAG trinucleotide repeats of SCA2and SCA2/PD patients in mainland China.Methods:We used the denatured PAGE, cloning sequencing and capillary electrophoresis to measure trinucleotide repeats and used SPSS Statistics22.0to make a statistical analysis.Results:We detected59SCA2families in713AD-SCA families (8.28%) and10SCA2patients in444S-SCA patients (2.25%); We also detected6PD-SCA2families in75autosomal dominant inheritance PD families (8%). The onset age of PD-SCA2patients is later than SCA2patients. Trinucleotide repeats of ATXN2gene of is related with age of onset of SCA2patients, but unrelated with PD-SCA2patients. Variations in repeat size account for58.9%of the variability in the age at onset. Besides, the mode of CAA interruptions and3’CCG interruptions are also related to the phenotype of SCA2or PD-SCA2.Conclusion:(1) SCA2is the second most common subtype of autosomal dominant spinocerebellar ataxia in Chinese han population, accounts for8.28%of all AD-SCA families and2.25%of sporadic patients;(2)ATXN2gene mutation can lead to the performance of Parkinson’s disease and can be the genetic cause of familial PD in mainland China;(3) ATXN2gene CAG trinucleotide repeats, CAA interruptions and3’CCG interruptions are related to the phenotype of SCA2and PD-SCA2.