Exome sequencing for Mendelian diseases first gained prominence in 2010 with the discovery of the disease gene for Miller syndrome and since then, mutations in several new ataxia genes have been identified utilizing exome sequencing, including ATP2B3, KCND3, DNMT1, UCHL1, and TPP1, illustrating the utility of the technology [11,12,13,14,15,16,17]. The gene discussed is ATP2B3; the disease is cerebellar ataxia.