Major risk factors for spontaneous LAR include advanced age, renal insufficiency and anticoagulant therapy; half of the patients show clinical characteristics of renal dysfunction.3,6 The etiologies and mechanisms involved in spontaneous LAR are known to be multifactorial, among which reduced adhesiveness and aggregation of platelets, lowered activity of platelet factor III, and impaired prothrombin consumption are the most common causes.10 Yamamura M et al.11 have suggested that muscle strain can induce LAR. The gene discussed is F2; the disease is Renal insufficiency.