Scientists have uncovered the basis of genetic variations in eight blood measurements and the impact those variants can have on common human diseases, according to a study published in Nature Genetics. Blood measurements, including the number and volume of cells in the blood, are routinely used to diagnose a wide range of disorders, including anemia, infection, and blood cell cancers.

 

An international team of scientists measured hemoglobin concentration — the count and volume of red and white cells and the sticky cells that prevent bleeding known as platelets – in more than 14,000 individuals from the United Kingdom and Germany. They uncovered 22 regions of the human genome found in the development of these blood cells. Of the 22 regions, 15 had not previously been identified.

 

“This unique collaboration has allowed us to discover novel genetic determinants of blood cell parameters, providing important insights into novel biological mechanisms underlying the formation of blood cells by the blood stem cells and their role in disease,” says co-lead of the HaemGen consortium Nicole Soranzo, group leader at the Wellcome Trust Sanger Institute.

 

The team compared regions of the human genome connected to blood cell development with regions associated with risk of heart disease. By comparing genetic data of 10,000 people with disease with that of 10,000 healthy people, they found that one of the genetic variants associated with platelet counts also causes an increased risk of heart disease. The new variant was found in a region of the genome already known to influence the risk of hypertension, celiac disease, and diabetes in children and young adults, or type 1 diabetes.

 

Further analysis showed that these genetic risk factors are uniquely found in individuals of European origin. By comparing human data with genetic data from chimpanzees, the researchers able to conclude that the genetic variant was the result of a selection event favoring variants that increase the risk of heart disease, celiac disease, and type 1 diabetes in European populations 3,400 years ago. The authors suggest that the risk factors were positively selected.

 

“The study of blood traits is challenging because of the difficulty of teasing apart biological processes underlying the origin of blood cells,” says and co-lead of the HaemGen consortium Christian Gieger, head of the Genetic Epidemiology research unit at the Helmholtz Zentrum. “Until now, few genome-wide association studies have looked beyond single traits. But, through a systematic analysis of correlated traits we can begin to discover such shared genetic variants, forming the basis for understanding how these processes interact to influence health and disease. Using these techniques, we can now begin to understand the complex genetic basis of a whole variety of human diseases.”