In brain tissue from patients with AD and HD, increased expression of fission-related genes such as dynamin related protein 1 (DRP1) and fission protein 1 (FIS1) and decreased expression of fusion-related genes such as MFN1, MFN2, and optic atrophy 1 (OPA1) have been reported, suggesting that excessive fission inducing apoptosis occurs [142,143]. This evidence concerns the gene DNM1L and Alzheimer disease.