Combined Oxidative Phosphorylation Deficiency 31 (COXPD31) is a multi-visceral disorder characterized by developmental delay, microcephaly, seizures, uncontrollable movements, and facial dysmorphy, as well as cardiac, muscular, and ophthalmic abnormalities. Clinical features present at birth or during infancy; the disorder is considered fatal due to the onset of progressive hypertrophic cardiomyopathy (left ventricular non-compaction). Additional symptoms include hypotonia, dystonic hypertonia, cataracts, and vision loss. Biochemical symptoms include increased lactate and alanine, fat and glycogen deposits in skeletal muscle, as well as abnormal mitochondria with reduced activity.
COXPD31 is caused by dysfunction in MIPEP, a gene essential for mitochondrial biogenesis and ATP production.