HMBS and hereditary coproporphyria: Acute hepatic porphyrias (AHPs) represents a rare group of four inherited metabolic disorders: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), with autosomal dominant trait inheritance caused by variants in the genes HBMS, PPOX and CPOX. These genes are responsible for encoding the porphobilinogen deaminase, protoporphyrinogen oxidase and coproporphyrinogen oxidase enzymes, respectively.