A novel AIFM1 missense mutation in a Japanese patient with ataxic sensory neuronopathy and hearing impairment

•A novel missense variant in AIFM1 was demonstrated in a Japanese patient. •Cardinal clinical features contained ataxic sensory neuronopathy and hearing impairment. •Impairment of OXPHOS was shown by aerobic exercise test. •No histopathological finding associated with mitochondrial dysfunction was shown. •A broad phenotypic and histopathological variations can be seen in AIFM1-related...