Table 1.

Types of porphyrias

Acute or Inducible Porphyrias	Abbreviation	Inheritance	Gene (Deficiency or Gain of Function)	Usual Age of Onset
ALA dehydratase deficiency porphyria	ADP	AR	ALAD (deficiency)	Infancy/childhood
Acute intermittent porphyria	AlP	AD	PBGD (deficiency)	Young adults
Hereditary coproporphyria	HCP	AD	CPOX (deficiency)	Adults
Variegate porphyria	VP	AD	PPOX (deficiency)	Adults
Chronic Hepatic Porphyrias
Hepatoerythropoietic porphyria	HEP	AR	UROD (deficiency)	Infancy/childhood
Sporadic porphyria cutanea tarda	sPCT	Acquired (AR, complex)	UROD (deficiency during active disease)	Adults
Familial porphyria cutanea tarda	fPCT	AD, complex	UROD (deficiency)	Young adults/adults
Erythropoietic Porphyrias
Congenital erythropoietic (Uro) porphyria	CEP	AR	URO3S (deficiency)	Infancy/childhood
Erythropoietic protoporphyria	EPP	AD	FECH (deficiency)	Infancy
X-Linked
X-linked protoporphyria	XLPP	X-linked	ALAS2 (gain)	Infancy

Notes: The porphyrias are classified by their major clinical manifestations (acute/chronic/erythropoietic/X-linked). Inheritance patterns and the gene products affected are also listed, as are the usual ages at which the diseases first become manifest. The familial form of PCT (fPCT) requires other risk factors, such as alcohol iron, hepatitis C, or HIV infection for clinical expression of disease. Most subjects with ~50% decrease in activity of UROD do not develop clinical disease, thus the “complex” AD inheritance.

Abbreviations: AD, autosomal dominant; ALA, 5-aminolevulinic acid; ALAD, ALA dehydratase; ALAS2, 5-aminolevulinate synthase 2; AR, autosomal recessive; CPOX, coproporphyrinogen oxidase; f, familial; FECH, ferrochelatase; PBGD, porphobilinogen deaminase; PPOX, protoporphyrinogen oxidase; UROD, uroporphyrinogen decarboxylase; URO3S, uroporphyrinogen 3 synthase.