Test Details: SCA1 is an autosomal dominant ataxia which manifests in early or middle adult life. It is characterized by progressive cerebellar ataxia of trunk & limbs, gait impairment, slow voluntary movements, scanning speech, tremors & nystagmoid eye movements. In SCA 1 there is a CAG trinucleotide repeat in chromosome 6 which gets affected and results in production of abnormal Ataxin-1 protein.