Bone Abstracts

Objectives: Erythropoietic protoporphyria (EPP) is a rare disease with cutaneous photosensitivity, in which patients avoid sun exposure and use sunscreen. Our purpose was to study bone mineral density (BMD), serum 25-OHD levels and other mineral parameters, to evaluate the impact of these measures in the follow-up of EPP patients.

Patients and methods: A ten EPP patients (median age 25; range 22–55, four males and six females), were study for clinical features, biochemical values (bone markers: serum osteocalcin, β-CTX and iPTH and 25-OHD) and lumbar and hip BMD (Hologic 4500 QDR) and serum porphyrins (total and free).

Results: Median serum 25(OH)D level was 19.65 ng/ml (17.50; 24.80). Four patients had 25(OH)D in insufficiency range (20–30 ng/ml) and five patients in the deficiency range (<20 ng/ml). Lumbar T-score median levels were in the osteopenia range in both females (−1.50 (−2.30; −1.0)) and males (−1.90 (−2.40; −0.70)). Also in the female group, femoral neck T-score were in the osteopenia range (−1.20 (−1.60; −0.60)). No correlation was found between levels of protoporphyrins and bone markers, BMD or 25OHD.

Conclusions: We report that low bone mass and vitamin D deficiency are frequent in EPP. The contribution of sunlight avoidance measures to this results remains to be clarified. The monitoring of serum vitamin D levels and BMD in EPP patients seems to be mandatory, adding vitamin D and calcium supplementation to their treatment protocol.