UGT1A1 polymorphism outweighs the modest effect of deletional (-3.7 kb) α-thalassemia on cholelithogenesis in sickle cell anemia

Enhanced erythrocyte destruction in sickle cell anemia results in chronic hyperbilirubinemia. Only a subset of patients develop cholelithiasis. UGT1A1 promoter polymorphism is associated both with unconjugated bilirubin level and elevated risk for cholelithiasis in such subset. Here, we investigated the role of alpha-thalassemia, yet another genetic factor that modulates hemolysis, in conferring protection from cholelithiasis. We show that, although alpha-thalassemia is associated with modest reduction in hemolysis and unconjugated bilirubin level, UGT1A1 polymorphism outweighs its effect on cholethiogenesis in sickle cell anemia patients.