A genome-wide meta-analysis identifies 22 loci associated with eight hematological parameters in the HaemGen consortium

Abstract
Nicole Soranzo and colleagues report a meta-analysis of genome-wide association datasets identifying 22 associations to 8 clinically relevant hematological traits. They also identify a long-range haplotype at 12q24 that includes variants associated with platelet counts as well as coronary artery disease and shows evidence of a selective sweep in Europeans. The number and volume of cells in the blood affect a wide range of disorders including cancer and cardiovascular, metabolic, infectious and immune conditions. We consider here the genetic variation in eight clinically relevant hematological parameters, including hemoglobin levels, red and white blood cell counts and platelet counts and volume. We describe common variants within 22 genetic loci reproducibly associated with these hematological parameters in 13,943 samples from six European population-based studies, including 6 associated with red blood cell parameters, 15 associated with platelet parameters and 1 associated with total white blood cell count. We further identified a long-range haplotype at 12q24 associated with coronary artery disease and myocardial infarction in 9,479 cases and 10,527 controls. We show that this haplotype demonstrates extensive disease pleiotropy, as it contains known risk loci for type 1 diabetes, hypertension and celiac disease and has been spread by a selective sweep specific to European and geographically nearby populations.