Porphyrias

Porphyria is a cluster of rare metabolic disease resulting from genetic defects in heme synthesis, leading to abnormal accumulation and deposition of toxic intermediates in neurologic and/or cutaneous tissue. The heme biosynthetic pathway enzymes are most active in the bone marrow and liver, and the intermediates are excreted in the bile and urine (turn to be reddish-purple in color). Porphyrias can be classified as either erythropoietic or hepatic, based on the site of accumulation of excess heme synthetic pathway intermediates. Erythropoietic porphyrias arise from the excess intermediates during the heme synthesis pathway and accumulates in the erythroid cells of the bone marrow. These conditions typically manifest at birth or early childhood with sensitivity to light, except for Congenital Erythropoietic Porphyria (CEP), which may appear in utero as nonimmune hydrops.