Risk for developing asthma is linked to variants in a gene called CHI3L1, which can be measured by checking levels of an inherited blood protein regulated by that gene, according to new research sponsored by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.

Researchers identified gene variants which are associated with increased susceptibility to asthma and reduced lung function in three study populations. The variants regulate the level of a blood protein called YKL-40, which, through previous NHLBI-funded research, has been shown to be elevated in people with asthma and correlate with asthma severity. This new research shows that the YLKL-40 protein is inherited, and can be measured from birth.

Building on the previous finding that the protein is a blood marker for asthma, researchers looked at the gene that regulates the protein. The relationship between the gene, the protein and asthma was first seen in a genetically and environmentally similar population, 700 members of an isolated religious community, the Hutterites, who are closely related and of European descent. The close-knit community has little exposure to smoking and similar exposures to environmental triggers for asthma. These factors make it easier to identify small differences in the genetic code.

Researchers then confirmed the connection between the gene and YKL-40 protein in three additional, more genetically diverse white groups in Chicago, Wisconsin, and Freiburg, Germany. In two of those populations, they confirmed the connection between the gene variants and asthma. One of the three groups, made up of 178 American children studied from birth in the NHLBI-funded Childhood Origins of Asthma (COAST) study, did not yet show a relationship between the gene and diagnosed asthma, but showed that the associations between YKL-40 levels and the gene variants were present at birth.

Release date: April 9, 2008
Source: National Institutes of Health