Pathophysiology associated with MOF and KANSL1 haploinsufficiency displays developmental and neurological impairments, which are also hallmarks of inherited mitochondrial diseases, including those of encephalomyopathy and Leigh syndrome associated with cytochrome c oxidase (COX) deficiency15,20,70. This evidence concerns the gene KANSL1 and mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria.