Four patients had missense mutation in genes associated with spinocerebellar ataxia, such as TTBK2 (exon 15, c.3467 G > A, p.Arg1156Gln in patient 11), TGM6 (exon 10, c.1478 C > T, p.Pro493Leu in patient 12), FGF14 (exon 1, c.31 A > G, p.Thr11Ala in patient 32), KCND3 (exon 4, c.1291 C > T, p.Arg431Cys in patient 33; Fig. 3C). Here, TTBK2 is linked to cerebellar ataxia.