MONDO_0013865 (mitochondrial hypertrophic cardiomyopathy with lactic acidosis due to MTO1 deficiency) is a rare mitochondrial oxidative phosphorylation disorder with complex I and IV deficiency characterized by lactic acidosis, hypotonia, hypertrophic cardiomyopathy and global developmental delay. Other clinical features include feeding difficulties, failure to thrive, seizures, optic atrophy and ataxia. Also known as: COXPD10, MTO1 combined oxidative phosphorylation deficiency, combined oxidative phosphorylation defect type 10, combined oxidative phosphorylation deficiency caused by mutation in MTO1, combined oxidative phosphorylation deficiency type 10.