Genotypic features of Spinocerebellar Ataxia in Northern China: A Comparative Analysis with Southern China.

Spinocerebellar ataxia (SCA) is a group of genetic neurodegenerative disorder characterised by progressive cerebellar and associated structural dysfunction. The prevalence of SCA subtypes are considerably variation among different ethnic groups and regions. However, the relative frequencies of these SCA subtypes remain understudied in northern Chinese populations. The study aimed to characterise the geographical heterogeneity of SCA subtypes between northern and southern China. We retrospectively analysed the genotypes and the clinical features of SCA patients primarily from northern China in Beijing Tiantan Hospital over the past five years. We compared the relative frequencies of subtypes found in the northern cohort with those reported in southern China. A total of 105 unrelated Chinese families were genetically verified, comprising 80 families from northern China and 25 families from southern China. Among the 80 families from northern China, SCA3 was identified in 46 families (57.5%), followed by SCA2 in 13 families (16.3%), SCA1 in 11 families (13.8%), SCA6 in 5 families (6.3%), and other SCA subtypes in the remaining 5 families (6.3%). A published cohort study conducted in southern China reported 102 genetically confirmed SCA families, including 74 families with SCA3.The comparative analysis revealed a significant decrease in the relative frequency of SCA3 in 80 families compared to a southern Chinese cohort of 102 families (72.5%, P < 0.05). Our data indicate a potential geographic variation in SCA subtype distribution, characterised by a lower relative frequency of SCA3 in northern China. Nationwide multi-center studies are required to validate the finding.