HADHA and long chain 3-hydroxyacyl-CoA dehydrogenase deficiency: Long-chain 3-hydroxyacyl CoA dehydrogenase deficiency (LCHADD, OMIM# 609016) is a rare, recessively inherited disorder of fatty acid oxidation (FAO) caused by the presence of a common pathogenic variant, c.1528 G > C, in at least one allele of the HADHA gene1,2.