NOS3 and Legg-Calve-Perthes disease: Polymorphisms and mutations such as FVL, COL2A1, G-455-A polymorphism of the β fibrinogen, MTHFR, eNOS polymorphisms, IL-6 polymorphism, and others related to LCPD have been reported in recent decades, showing genetics as a central etiological factor in LCPD [5,6,7,8,21,22,23,24,25,26,27,28,29,30,31].