The most common causative genes identified in each clinical subgroups were: CACNA1A (n = 2) in pure ataxia; SPG7 (n = 13) in spastic ataxia; RFC1 (n = 17) in sensory ataxia; SPG7 (n = 6) in ataxia with metabolic features; ATXN3, RFC, SPG7 (n = 2 each) in late complex ataxia; and CACNA1A (n = 6) in episodic ataxia. The gene discussed is CACNA1A; the disease is cerebellar ataxia.