ACAD9 and Leigh syndrome: Phenotype diversity of Leigh disease has been reported for m.8993T>C mutation in the same MT-ATP6 gene [81]; noticeably, other unusual presentations rather than neurological ones were found with other mitochondrial and nuclear-encoded genes, causing Leigh disease to be ocular and gastrointestinal with MT-ND mutations [82,83], cardiac with NDUF [84,85] and renal with SURF1 and ACAD9 gene defects [86,87].