A heterozygous single point mutation in the CACNA1G gene which causes an arginine-to-histidine (p.Arg1715His) change in the S4 voltage-sensing region of the T-type voltage-gated Ca2+ channel protein Ca(v)3.1 has concurrently been associated to SCA42 in ten families [64,65,66,67]. This evidence concerns the gene CACNA1G and spinocerebellar ataxia type 42.