[Hereditary porphyria cutanea in children. Enzymatic studies (author's transl)].

A girl of 7 years presenting porphyria cutanea tarda was found to have a very low level of erythrocytary uroporphyrinogen decarboxylase. Tests on her brother, parents and maternal grand-parents, who were all free of the disease revealed the same level of enzyme in the mother and grandmother, through whom the hereditary factor was obviously transmitted. This supports evidence provided by juvenile cases and familial forms in the literature that heredity plays an important part in a disease which is often considered to be acquired or symptomatic. Despite clinical and biological resemblances, two types of porphyria cutanea can be distinguished: a sporadic form in which enzyme deficiency occurs only in the liver and is revealed by exogenous toxic factors such as alcohol or oestrogens and an hereditary form where the deficiency transmitted by a dominant autosomal mode is found in all hemasynthetising cells.