Extensive investigations have shown that heterozygous mutations in AFG3L2 are responsible for autosomal dominant spinocerebellar ataxia type 28 (SCA28) [11], while homozygous mutations in AFG3L2 are associated with autosomal recessive spastic ataxia syndrome (SPAX5) [12]. The gene discussed is AFG3L2; the disease is spinocerebellar ataxia type 28.