The researchers included children from two separate study groups, all of whom came from families with a history of allergies or asthma. The first group included 200 children toddlers with at least one, and possibly two parents who had allergies or asthma while the second group consisted of Danish toddlers whose mothers were diagnosed with asthma. Among children without the high-risk genetic variants for asthma, 40% who wheezed when they caught a cold before age three developed asthma by age six, compared to 60% who had one copy of the variant and wheezed, and 90% of those who had two copies and also wheezed.
“We found that the interaction between this specific wheezing illness and a gene or genes on a region of chromosome 17 determines childhood asthma risk. The combination of genetic predisposition and the child’s response to this infection has a huge effect,” said study author Carole Ober, a Blum-Riese Professor of Human Genetics at the University of Chicago in a statement.