F9 and Legg-Calve-Perthes disease: Additionally, researchers analyzed blood and plasma samples from 25 LCPD patients and 50 healthy controls, discovering reduced prothrombin time and elevated levels of factor V Leiden, factor VIII, factor IX, and Hcy in LCPD patients (Hernández-Zamora et al., 2023), potentially explaining the coagulation abnormalities in these patients.