brain disorder mitochondrial oxidative phosphorylation disorder encephalopathy due to mitochondrial and peroxisomal fission defect https://www.malacards.org/card/encephalopathy_due_to_mitochondrial_and_peroxisomal_fission_defect MEDGEN:1814479 GARD:0022192 encephalopathy due to defective mitochondrial and peroxisomal fission encephalopathy due to mitochondrial and peroxisomal fission defect MONDO:0054865 OMIMPS:614388 UMLS:C5681458 A rare mitochondrial disease characterized by a variable phenotype comprising delayed psychomotor development or neurodevelopmental regression, hypotonia, seizures, microcephaly, optic atrophy, pyramidal signs, and peripheral neuropathy, among others. Age of onset and disease severity are also variable with some cases taking a fatal course in early infancy. Serum lactate levels may be elevated. Reported brain imaging findings include abnormal signals in the basal ganglia, cerebral and/or cerebellar atrophy, and white matter abnormalities. Orphanet:527276 disorder of defective peroxisomal and mitochondrial fission hereditary neurological disease