Wheezing May Reveal Higher Risk of Asthma in Toddlers

If your toddler wheezes when he or she is sick, it could be a sign that they are at risk of developing asthma. Wheezing-related illnesses are already known to increase the risk of tots becoming asthmatic when combined with certain genetic factors.

Now a study by the University of Chicago has revealed that 90% of three-year-olds who have a specific chromosome and who suffer from an infection known as rhinovirus will go on to be diagnosed with asthma by the time they are six years old. Rhinovirus is the most predominant cause of the common cold.

The research examined a region of chromosome 17, called 17q21, which is linked to an increased risk of asthma in very young children. The findings suggest that a combination of the genes in 17q21 and wheezing illnesses such as the common cold make a child almost four times as likely to develop asthma as children without the genetic variation or the wheezing. The Chicago team concluded that wheezing could be an indicator of a toddler’s risk of later developing asthma.

Their study focused on two common genes contained within 17q21, known as ORMDL3 and GSDMB, variants of which are considered likely to cause a higher risk of wheezing in children who have the rhinovirus. Half of all children in the study had one copy of the variant and a quarter had both, while all children came from families in which there was a history of asthma or allergies.

The connection between the genes and wheezing is not yet known. In an extension of their work, the researchers exposed the immune cells in the blood of 100 healthy adults to human rhinovirus, revealing that the cold virus appeared to increase the activity of the asthma-related genes in chromosome 17. This has the potential to cause more wheezing.

Testing of toddlers could reveal if they have the genetic variant that would make them more susceptible to developing asthma and if so, parents can reduce their exposure to the common triggers of the chronic condition of the airways, such as air pollution, animal dander and cigarette smoke.