The human genes ADCK3 and ADCK4, also known as COQ8A and COQ8B, are both homologs of yeast COQ8. Mutations in COQ8A have mostly been associated with autosomal recessive progressive cerebellar ataxia (ARCA), often accompanied by childhood onset cerebellar atrophy, with and without seizures, and exercise intolerance [241,248,275]. The gene discussed is COQ8A; the disease is autosomal recessive cerebellar ataxia.