Variegate porphyria (VP) is both a cutaneous porphyria (with chronic blistering skin lesions) and an acute porphyria (with severe episodic neurovisceral symptoms). The most common manifestation of VP is adult-onset cutaneous blistering lesions (subepidermal vesicles, bullae, and erosions that crust over and heal slowly) of sun-exposed skin, especially the hands and face. Other chronic skin findings include milia, scarring, thickening, and areas of decreased and increased skin pigmentation. Facial hyperpigmentation and hypertrichosis may occur. Cutaneous manifestations may improve in winter and be less prevalent in northern regions and in dark-skinned individuals. Acute neurovisceral symptoms can occur any time after puberty, but less often in the elderly. Acute manifestations are highly variable, but may be similar from episode to episode in a person with recurrent attacks; not all manifestations are present in a single episode; and acute symptoms may become chronic. Symptoms are more common in women than men. The most common manifestations are abdominal pain; constipation; pain in the back, chest, and extremities; anxiety; seizures; and a primarily motor neuropathy resulting in muscle weakness that may progress to quadriparesis and respiratory paralysis. Psychiatric disturbances and autonomic neuropathy can also be observed. Acute attacks may be severe and are potentially fatal.

Familial porphyria cutanea tarda (F-PCT) is characterized by: skin findings including blistering over the dorsal aspects of the hands and other sun-exposed areas of skin, skin friability after minor trauma, facial hypertrichosis and hyperpigmentation, and severe thickening of affected skin areas (pseudoscleroderma); and an increased risk for hepatocellular carcinoma (HCC).

De Verneuil et al. (1978) classified porphyria cutanea tarda (PCT), the most common type of porphyria, into 2 types: type I, or 'sporadic' type, associated with approximately 50% level of uroporphyrinogen decarboxylase (UROD; 613521) in liver (Elder et al., 1978; Felsher et al., 1982), and type II, or 'familial' type (176100), characterized by 50% deficient activity of the same enzyme in many tissues (Kushner et al., 1976; Elder et al., 1980). Type I is the most common form of PCT, comprising 70 to 80% of cases. The causes of the deficiency are often unclear and are probably multifactorial (review by Lambrecht et al., 2007).