An inherited enzymatic defect in porphyria cutanea tarda: decreased uroporphyrinogen decarboxylase activity.

Abstract

A B S T R A C T Uroporphyrinogen decarboxylaseWith the erythrocyte assay, multiple examples of decreased uroporphyrinogen decarboxylase activity were detected in members of three families of patients with porphyria cutanea tarda. In two of these families subclinical porphyria was also recognized. The inheritance pattern was consistant with an autosomal dominant trait.The difference in erythrocyte enzymatic activity between men and women was not explained but could have been due to estrogens. This possibility was supported by the observation that men under therapy with estrogens for carcinoma of the prostate had values in the normal female range.

Three new mutations in the uroporphyrinogen decarboxylase gene in familial porphyria cutanea tarda

“…Erythrocyte activity and immunoreactivity: The reductions observed in patient erythrocyte UROD activity and immunoreactivity (data not shown) are consistent with previous findings in fPCT (Kushner et al 1976, Elder et al 1977, Elder et al 1978, de Verneuil et al 1978. Low UROD activity was also observed in at least one other family member with the exception of family #2 (GA) where a clinically affected family member was not available for testing.…”

Large phlebotomy in variegate porphyria

“…The patient in this report deviates from previously studied individuals with PCT-VP dual porphyria [2][3][4][5] in the respect that her faecal porphyrin excretion, albeit deviating from normal, gave no indication of PCT (this was, in fact, the main reason for the later actualization of the VP diagnosis). It also deviates from these previous reports as the normal erythrocyte uroporphyrinogen decarboxylase activity indicated a sporadic type of PCT [11]. Since chloroquine is a therapeutic option in PCT, but possibly porphyrinogenic in VP [21], the experiences from the present case demonstrate the value of extending the biochemical investigation of a patient with bullous dermatosis to include a check of the faecal porphyrin pattern even if the urinary findings are indicative of PCT.…”

“…On the basis of a finding of increased urinary excretion of polycarboxylated porphyrins, the diagnosis of PCT was established. Normal activity of erythrocyte uroporphyrinogen decarboxylase classified the condition as the sporadic type [11]. During a May-October period in 1993, 12 therapeutic phlebotomies, 300 mL each, were performed, which resulted in slow healing of the skin condition with development of coin-sized scars.…”

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.…”