AFG3L2 homozygous knockout mice dis

AFG3L2 homozygous knockout mice display severespasticity, premature death, and impairment of axonaldevelopment and myelination in the nervous system,whereas heterozygous mice show late-onset cerebellardegeneration. Mitochondria isolated from these miceshowed impaired ATP synthesis and reduced assembly ofrespiratory complexes I and III as observed in one of ourpatients.2,12-14 In humans, almost the same findings havebeen observed. Most cases in the literature with AFG3L2 areof milder cases with heterozygous mutations presentingwith progressive ataxia (SCA28) compared with homozygousmutations. It seems that recessive mutations in thisgene cause a much more severe phenotype, which is progressiveand can lead to death.4