A rare mitochondrial oxidative phosphorylation disorder characterised by progressive generalised hypotonia, progressive external ophthalmoplegia and severe lactic acidosis, which result in early fatality (days to months after birth). Patients may present with lethargy and areflexia and may associate additional features, such as cardiomyopathy, renal dysfunction, liver involvement and seizures. [from
SNOMEDCT_US]