Two large international studies shed light on the genetics behind blood diseases and suggest polygenic risk scores can be used to predict the likelihood that someone will develop one of these conditions.
The two studies are published in the journal Cell and identified thousands of genomic regions involved in the formation of blood and blood cells and variants linked to diseases such as anemia or hemochromatosis across many different human populations.
The first study was a large genome-wide association study and included 563,085 participants of European ancestry. Of these, 408,112 of them were from the UK Biobank and 154,973 from the Blood Cell Consortium.
The team working on this study, led by researchers from the Broad Institute and the Wellcome Sanger Institute in the UK, discovered more than 5000 new genetic variants that were associated with 29 different features of the blood. For example, average platelet volume or whole blood count.
“This study indicates that polygenic scores could be used routinely in personalised medicine in future, following further research,” said Nicole Soranzo, Ph.D., co-lead author of the study from the Wellcome Sanger Institute and University of Cambridge.
“If a person is more genetically predisposed to low hemoglobin, for example, then they are more likely to develop anaemia,” added Dragana Vuckovic, Ph.D., co-first author of the study and also from the Wellcome Sanger Institute.
The researchers also tested whether a polygenetic risk score made up of genetic variation across a selection of different genes associated with blood could predict physiological differences. They found that it could, although the impact of genetics varied depending on the trait they were looking at. For example, the genetic score accounted for only 2.5% of variation in the level of basophil white blood cells, but 27% of variation in platelet volume.
The second study, led by researchers at the University of Wisconsin-Milwaukee and University of Montreal, focused on finding genetic variants associated with blood formation and diseases across non-European populations. The team studied samples from 746,667 in total, including 184,535 non-Europeans.
They discovered more than 5,000 associations with different traits in the blood. Notably, more than 70 of these were not found in European populations. For example, a variant in the IL7 gene found in South Asians was linked to levels of lymphocyte white blood cells.
“These results… highlight a need for large genetic analyses in other populations… As more studies seek to unravel the causal variants that underlie complex traits associations, we anticipate that genetic evidence from diverse ancestries will play an important role,” write the authors.