GTPBP3 and hypertrophic cardiomyopathy: MTO1 mutations cause combined oxidative phosphorylation deficiency 10 (COXPD10), presenting with infantile hypertrophic cardiomyopathy and lactic acidosis, while GTPBP3 mutations cause COXPD23, characterized by early childhood hypertrophic cardiomyopathy and neurological symptoms [140].