DDC and thalassemia: The new candidates accounted for the remaining 19.2% of the explainable variation, with USP38 (8.1%), DDC (3.8%), FREM3 (3.0%), SDC1 (2.6%), and LOC727982 (1.7%) all accounting for more variation than ABO blood group and α-thalassemia but in aggregate less than the sickle HbAS polymorphism.