F5 and Legg-Calve-Perthes disease: The presence of Factor V Leiden (FVL) and prothrombin C20210A mutations, deficiencies in proteins C and S, elevated levels of lipoprotein (a) or fibrinogen, as well as FV and FVIII hyperactivity have been reported in populations with LCPD [2,3,4,5,6].