PROS1 and Prader-Willi syndrome: Disturbances in F2 (thrombin), F5 (coagulation factor 5) and other genes such as PROC (protein C), SERPINC1 (serpin family C member 1) and PROS1 (protein S) can produce both autosomal-dominant and autosomal-recessive patterns of inheritance of blood clots in families (https://www.omim.org), and more studies are required to possibly differentiate their role in arterial and venous thromboses impacted by age of onset in both PWS patients and obese controls.