Mutations in AIFM1 cause an X-linked childhood cerebellar ataxia partially responsive to riboflavin.

•AIFM1 encodes a mitochondrial NADH oxidoreductase and regulator of apoptosis, that uses riboflavin as a cofactor.•Mutations in AIFM1 gene may cause ataxia, accompanied by axonal neuropathy and sensorineural hearing loss.•Auditory neuropathy, a special type of sensorineural hearing loss, is characteristic for AIFM1 dysfunction.•Severe myoclonus, presenting as status myoclonicus, should be added to the AIFM1 related ataxia phenotype.•Treatment with riboflavin might be beneficial for improving ataxia score in these patients.