New aspects of porphyrias

The porphyrias: a brief overview based on 25 years of experience (1969-1994) by the Department of Dermatology of the Hospital Clinic and Faculty of Medicine of Barcelona, Spain

The porphyrias are uncommon diseases caused by enzymatic deficiencies in the heme pathway. In the 25 year period 1969-1994, the Department of Dermatology of the Hospital Clinic of Barcelona has been able to study 793 cases of porphyria (724 cases of PCT, 27 of EPP, 26 of PV, 5 of CEP, 5 of HEP, 5 of AIP, 1 of HCP). Homozygous expression of an enzymatic deficiency in the heme pathway produces severe disease. Commonly, clinical manifestations appear in the homozygous state (the autosomal recessive porphyrias). However, homozygous forms of autosomal dominant porphyrias may occur exceptionally. Moreover, there are cutaneous porphyrias whose clinical manifestations do not permit dermatologists to classify them clearly into one of the well-defined syndromes. These uncommon and atypical forms are difficult to recognize without biochemical and enzyme studies. The porphyrias have a wide clinico-biochemical spectrum, including a large proportion of well defined diseases. Nevertheless, atypical forms occur and may be difficult to evaluate. It is important to note the genetic heterogeneicity of porphyrias, which accounts for the varying phenotypic expression.

Cutaneous porphyrias in China

In China, 78 cases of cutaneous porphyrias, together with 67 cases reported by other clinicians from 1979 to 1990, were reviewed. Of a total of 145 cases, 75.2% were EPP (109 cases), but only 28 cases (19.3%) were PCT. This prevalence differs from that in other parts of the world. The article discussed this disparity and some notable points. Early diagnosis of EPP using the fluorescence microscopic test for determination of RBC protoporphyrin is important. The complication of hepatobiliary aspects in PCT and EPP was noticed. Liver disease seems to be an important precipitating factor in China.