Erythropoietic protoporphyria in Sweden: demographic, clinical, biochemical and genetic characteristics

Abstract

Design. Cross-sectional questionnaire, biochemical and genetic study. Setting. Sweden.Subjects. Fifty-one Swedish individuals known in 2008 to have EPP confirmed by molecular diagnosis. There were no exclusion criteria; all patients were included in the demographic and genetic study. A total of 92% participants completed the questionnaire study and 82% the biochemical study.Results. The prevalence of EPP was 1 : 180 000. Nine novel ferrochelatase gene mutations were found. The most commonly reported age at onset of symptoms was the first year of life and the mean age at diagnosis was 22 years. Painful photosensitivity was the main symptom. Exogenous factors other than sunlight were frequently reported to cause cutaneous symptoms. One in five patients reported a positive effect of beta-carotene therapy. A marked impact of EPP on quality of life was reported. Women had a significantly lower mean erythrocyte protoporphyrin concentration than men. Of all participants, 84% had insufficient vitamin D concentrations, 44% had below normal serum ferritin or transferrin saturation levels and red cell abnormalities were common.Conclusions. The notably delayed diagnosis suggests the need for an increased awareness of EPP. Disturbed erythropoiesis, biochemical signs of iron deficiency and low vitamin D levels are frequent findings in this disease. New and better treatments are needed as current treatment options for symptom amelioration are limited. Vitamin D supplementation should be considered.

Porfyrisykdommer i Norge

“…Recent studies (17,18) have shown that patients with erythropoietic protoporphyria have a severely reduced quality of life, which is partly explained by the long diagnostic delay, major restrictions on daily living and the fact that there are few treatment options. In light of the fact that several of the porphyrias may have long diagnostic delays, may cause severe and/or pronounced distress and are dependent on life-long follow-up, new studies are needed to assess the need for follow-up and help for porphyria patients at different stages of life.…”

“…The disease is diagnostically challenging, not only because it is very rare, but also because the clinical presentation may be a small child who cries and is agitated when exposed to the sun, without this being accompanied by distinct skin lesions (1). This study includes too few patients with erythropoietic protoporphyria to allow us to investigate whether time to diagnosis is shorter now than in the past, but the studies from Sweden and the UK have failed to demonstrate any change (17,18).…”

Clinical, Biochemical and Molecular Characteristics of the Main Types of Porphyria

“…The enzyme deficiency is caused by mutations in the FECH gene which is located on chromosome 18q21.3. To date, 190 mutations responsible for EPP have been described [13,19,31].…”

“…Cholelithiasis due to gallstones containing protoporphyrin is reported in about 25% of EPP patients. Liver failure affects 2-5% of patients; many present iron deficiency with microcytic anemia and low vitamin D levels [1,13,31].…”

“…In Sweden the EPP prevalence is 1/180 000 [13], in Slovenia 1.75/100 000 [14]. CEP is very rare; to date approximately 150 cases have been reported [9].…”