Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a mitochondrial disorder of long chain fatty acid oxidation characterized in most patients by onset in infancy/ early childhood with hypoketotic hypoglycemia, metabolic acidosis, liver disease, hypotonia and frequently cardiac involvement with arrhythmias and/or cardiomyopathy. The disease is Monarch Disease Ontology identifier MONDO_0012173 (long chain 3-hydroxyacyl-CoA dehydrogenase deficiency). Also known as: HELLP syndrome, maternal, of pregnancy, LCHAD deficiency, LCHADD, fatty liver, acute, of pregnancy, long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency.