Rare, hereditary, mitochondrial oxidative phosphorylation disorder characterized by severe neonatal lactic acidosis and deficiency of mitochondrial complexes I, II and III. Clinical features are variable and may include hypotonia, respiratory distress with cyanosis, failure to thrive, feeding difficulties, hypoglycemia, dehydration, vomiting, seizures, and a risk of multiple organ failure. The disease is severe neonatal lactic acidosis due to NFS1-ISD11 complex deficiency (MONDO_0700371, a Monarch Disease Ontology id).