Acute Intermittent Porphyria in a Man with Dual Enzyme Deficiencies

Abstract

Porphyrias are a heterogeneous group of metabolic disorders that result from the altered activity of specific enzymes of the hemebiosynthetic pathway and are characterized by accumulation of pathway intermediates. Porphyria cutanea tarda (PCT) is the mostcommon porphyria and is due to deficient activity of uroporphyrinogen decarboxylase (UROD). Acute intermittent porphyria(AIP) is the most common of the acute hepatic porphyrias, caused by decreased activity of hydroxymethylbilane synthase(HMBS). An Argentinean man with a family history of PCT who carried the UROD variant c.10_11insA suffered severe abdominalpain. Biochemical testing was consistent with AIP, and molecular analysis of HMBS revealed a de novo variant:c.344 + 2_ + 5delTAAG. *is is one of the few cases of porphyria identified with both UROD and HMBS mutations and the firstconfirmed case of porphyria with dual enzyme deficiencies in Argentina.