CACNA1A and spinocerebellar ataxia type 6: On the other hand, spinocerebellar ataxia type 6 (SCA6) [3], which is caused by an abnormal expansion of CAG repeats in exon 47 of the CACNA1A gene, is characterized by slowly progressive cerebellar ataxia, but rarely presents with episodic ataxia-like symptoms [4].