Two paediatric cases of erythropoietic protoporphyria

Key words: Erythropoietic protoporphyria, Photosensitivity, Afamelanotide, Cimetidine

The article reports two cases of a rare paediatric disease: erythropoietic protoporphyria (EPP) characterized by burning erythema and variable liver damage. EPP is the most common porphyria in children, caused by mutations in ferrochelatase (FECH) gene, which is the last enzyme along the haem biosynthetic pathway. Consequently, haem precursor protoporphyrin IX accumulates in erythrocytes, plasma, skin and liver. The clinical features are: photosensitivity (pain, itching, burning along with oedema and/or erythema in sun-exposed areas), mild anaemia, and a variable degree of hepato-biliary disease with potential cholelithiasis and, in 1-5% of patients, end-stage liver disease. Diagnosis is made by finding elevated erythrocyte protoporphyrin and confirmed by molecular genetic testing in FECH gene. Therapy is based on sun protection, vitamin D, and beta-carotene, along with ursodeoxycholic acid and/or cholestyramine if hepatobiliary disease is present. Afamelanotide and cimetidine have shown efficacy in treating photo-sensitivity, but do not prevent liver damage, so that a tight follow-up is needed.