TY - CHAP M1 - Book, Section TI - Disorders of Heme Biosynthesis: The Porphyrias A1 - Desnick, Robert J. A1 - Balwani, Manisha A2 - Kline, Mark W. PY - 2018 T2 - Rudolph's Pediatrics, 23e AB - The porphyrias are a group of inherited and acquired metabolic disorders, each resulting from the deficient or increased activity of a specific enzyme in the heme biosynthetic pathway. These enzyme alterations are inherited as autosomal-dominant or -recessive and X-linked traits, with the exception of porphyria cutanea tarda (PCT), which usually is sporadic. These disorders are classified as either hepatic or erythropoietic, depending on the primary site of overproduction and accumulation of the porphyrin precursor(s) or porphyrin(s) (Table 162-1). Clinically, they are classified as acute and cutaneous, although some have overlapping features. Manifestations of the acute hepatic porphyrias are primarily neurologic, including severe abdominal pain, neuropathy, and secondary mental symptoms, whereas the erythropoietic porphyrias characteristically cause cutaneous phototoxicity. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accesspediatrics.mhmedical.com/content.aspx?aid=1182930237 ER -