Thirty-four new genetic regions are associated with blood cell traits, according to four independent studies published online in this week's Nature Genetics. These studies provide new insights into genetic loci that regulate variation in blood cell traits.

The number and volume of blood cells are commonly measured in the clinic to help diagnose many diseases and manage treatment, including cancer and cardiovascular, metabolic, infectious, and immune disorders. Nicole Soranzo, Santhi Ganesh and colleagues analyzed the genomes and measured blood traits in nearly 50,000 individuals. Together, the studies report more than 25 new genetic variants that are associated with clinically relevant blood traits, including hemoglobin levels and number and volume of red and white blood cells and platelets.

Beben Benyamin, John Chambers, Jaspal Kooner and colleagues independently verified that the gene TMPRSS6 ― also identified by Soranzo and Ganesh ― is associated with blood hemoglobin levels. Since defects in TMPRSS6 have previously been linked to patients with iron-refractory iron-deficiency anemia, these findings show that TMPRSS6 is involved in control of iron levels in the general population as well.