Spinocerebellar ataxias (SCA) 1, 2, 3 and 6 are the most common, autosomal dominantly inherited cerebellar degenerations. And in the Chinese population, the most common SCA is SCA3 and the frequency of SCA 3 among SCA patients is 72.5%, followed by SCA 2 that the frequency is 12% among SCA patients. For SCA 1, the frequency among SCA patients is 7%. Even SCAs are rare diseases, a significant amount of Chinese in Hong Kong still suffer from this disorders. SCA Association in Hong Kong has 88 members who are suffering from spinocerebellar degeneration, many of them have a genetic confirmation. As there are few treatments for SCAs; therefore, understanding SCAs clinical manifestation and disease mechanisms are the first step towards development of effective treatment. The objective of this study is to develop the first SCA registry in Hong Kong with bio-repository bank for clinical and genetic information as well as serum and fibroblasts.