Six genes (CPS1 [MIM: 608307], PYGB [MIM: 138550], MARCH10 [MIM: 613337], SLC4A5 [MIM: 609802], NADSYN1 [MIM: 608285], and CACNA1H [MIM: 607904]) were common to all three SCA groups (Table S1). The gene discussed is PYGB; the disease is autosomal dominant cerebellar ataxia.