Multiple osteonecroses and venous thrombosis: one case of patient with a novel mutation of protein C (N102S) and heterozygous for FV Leiden

The association of a thrombo-embolic venous disease and multiple osteonecroses occurring in the presence of biological risk factors for thrombosis is rarely described in the literature. We report here the case of a 35-year old patient with such clinical manifestations. This patient is heterozygous for a novel mutation of the protein C gene (N102S) and for FV Leiden polymorphism. The clinical history is characterized by numerous thrombo-embolic venous episodes associated with several episodes of epiphysis osteonecrosis requiring two hip total prostheses and two knee total prostheses. The particular clinical features here are the multiple osteonecroses and the unusual localisation of brain and genital thromboses. The absence of both venous thromboembolic and osteonecrosis events in the relatives presenting the same genetic pattern suggests broad phenotype variations in the clinical expression of these genetic abnormalities. In osteonecrosis associated with thrombophilia, some authors have proposed treatment with stanazolol, which increase circulating protein C concentration. The effectiveness of this drug among such patients should be evaluated by clinical studies.