deafness-encephaloneuropathy-obesity-valvulopathy syndrome (MONDO_0013837) is a rare mitochondrial disease with marked clinical variability typically characterized by encephalomyopathy, kidney disease (nephrotic syndrome), optic atrophy, early-onset deafness, pancytopenia, obesity, and cardiac disease (valvulopathy). Additionally, macrocephaly, intellectual disability, hyperlactatemia, elevated lactate/pyruvate ratio, insulin-dependent diabetes, livedo reticularis, liver dysfunction and seizures have also been associated. Also known as: coenzyme Q10 deficiency, primary, type 2, hearing loss-encephaloneuropathy-obesity-valvulopathy syndrome.