Genetic disorders with heterotopic ossificans.

Fibrodysplasia ossificans progressiva (FOP) and progressive ossific heteroplasia (POH) are rare genetic disorders characterized by heterotopic bone formation leading to progressive loss of mobility and function. We report three cases of these rare disorders (two cases of FOP and one case of POH), which were clinically diagnosed and underwent genetic analysis. The aim of this report is to highlight the clinical features and the differences between these two conditions. We would also like to emphasize on the morbidity that can arise from unnecessary invasive investigations for diagnostic purposes.