Despite a strong suspected link between genetics and asthma, commonly found genetic mutations account for only a small part of the risk for developing the disease - a problem known as missing heritability. Rare and low-frequency genetic mutations have been thought to explain missing heritability, but it appears they are unlikely to play a major role, according to a new study led by scientists from the University of Chicago, and including collaborators from Johns Hopkins, the University of California-San Francisco (UCSF), Harvard Medical School, the University of Arizona, the University of Wisconsin-Madison, and other institutions. Analyzing the coding regions of genomes of more than 11,000 individuals, the researchers identified mutations in just three genes that were associated with asthma risk. Each was associated with risk in specific ethnicities. The findings, published online in an open-access article in Nature Communications on January 16, 2015, suggest gaps in the current understanding of asthma genetics. "Previous studies have likely overestimated the heritability of asthma," said study senior author Carole Ober, Ph.D., Blum-Riese Professor and Chair of the Department of Human Genetics at the University of Chicago. "This could be because those estimates are based on correlations between family members that share environment as well as genes, which could inflate the heritability. Gene-environment interactions are not considered in these large-scale association studies, and we know that these are particularly important in establishing individual risks for asthma."
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