Acquired fluctuations in protein S levels may arise from factors such as vitamin K antagonist (VKA) use, chronic infection, severe hepatic disease, systemic lupus erythematosus (SLE), myeloproliferative disorders, renal syndromes, disseminated intravascular coagulation, and oral contraceptive use [5]. The gene discussed is PROS1; the disease is Disseminated intravascular coagulation.