Erythrocyte Uropophyrinogen Decarboxylase Activity in Porphyria Cutanea Tarda: A study of 40 Consecutive Patients.

Abstract

We measured uroporphyrinogen decarboxylase (UROD) activity in erythrocyte lysates obtained from 40 consecutive patients with porphyria cutanea tarda (PCT) without selection for family history. Enzyme determinations indicated that 28% of the patients had abnormally decreased UROD activity in erythrocytes; this finding did not always correlate with family history. Two siblings with PCT and normal erythrocytic, but abnormally decreased hepatic UROD activities, were encountered. This finding suggests that familial PCT may occur not only with decreased erythrocyte UROD activity, but also with a normal UROD activity in erythrocytes.

Porfiria cutânea tardia

“…5 In the past, it was found mostly in men, but the current incidence in women, 6 is increasing due to the intake of estrogens and to the increase in alcohol consumption. 7 The disclosure of low Urod activity in PCT promoted its subdivision: 8 Sporadic porphyria cutanea tarda (Type I, symptomatic or acquired) -It encompasses 72% to 84% of cases, [9][10][11] and the enzyme deficiency is restricted to the liver, with normal erythrocyte Urod activity. 12 There is no family history.…”

“…Urod activity is reduced to half normal in all tissues (erythrocytes and liver) due to reduction in enzyme synthesis or stability. 10,11,14,15 Differentiation between PCT types I and II cannot be solely based on erythrocyte Urod activity, which may be at the lower limit in PCT type II and below the normal interval in PCT type I. 10,16 Thus, DNA testing is preferred for the identification of familial cases.…”

“…10,11,14,15 Differentiation between PCT types I and II cannot be solely based on erythrocyte Urod activity, which may be at the lower limit in PCT type II and below the normal interval in PCT type I. 10,16 Thus, DNA testing is preferred for the identification of familial cases. 7 Mutations in the Urod gene discriminate familial from sporadic forms.…”

“…The promoter region and the coding DNA sequence of Urod are normal, suggesting that other loci are involved in its pathogenesis, and these may be genes affecting tissue iron. 10,13 It is not proven that type III PCT is a distinct form of the disease or if it would be PCT type I with inherited contribution. 11…”

Porphyria cutanea tarda in the HFE-gene and hepatitis C virus era

“…In familial (type II) PCT, there are a variety of autosomal dominantly inherited gene abnormalities that display a low penetrance (4). There is some evidence for a putative third type of PCT that appears to be a familial form of type I PCT (5,6). Finally, there is a toxic form of PCT in which exposure to aromatic hepatotoxic hydrocarbons results in a cutaneous eruption similar to that of sporadic PCT; this forms the basis of an animal experimental model for PCT (7).…”