Identification of two genetic abnormalities increasing sensitivity to passive smoking

Chronic exposure to cigarette smoke results in some children and adolescents develop serious respiratory problems such as asthma, while others do not seem to be particularly affected.

A team from the Faculty of Medicine at Dundee, Scotland, think I found the reason for this difference in sensitivity to passive smoking, with the discovery of two genetic abnormalities that increase the risk of asthma and aggravating the deterioration of lung function in asthmatics when exposed to cigarette smoke.

Dr. Somnath Mukhopadhyay, a pediatrician, and his colleague Dr. Colin Palmer, a molecular geneticist at the Centre for Biomedical Research, observed 600 asthmatic children and adolescents in whom they measured the peak expiratory flow (PEF) and examined the genes involved in the elimination of toxins inhaled.

These genes indeed help the body produce glutathione S-transferase, an enzyme particularly effective for detoxifying inhaled tobacco smoke in the lungs. They are however subject to two common abnormalities present in one half of the population, the other in about 12% of cases.

The researchers found that adolescents with one or the other of these anomalies and exposed to cigarette smoke have a lower DEP 15% that measured adolescents not victims of passive smoking asthmatics.

"The risk is that these children and adolescents, which naturally unaware of their status vis-à-vis the sensitivity resulting from this genetic abnormality, can endure a silent and long-term decline in lung function for several years," says Dr. Mukhopadhyay. And "this can engender a greater subsequent risk of chronic obstructive pulmonary disease (COPD)," he adds.

Scotland has the highest prevalence in the world of asthma in adolescents. It is also the country of the United Kingdom, where the rate of COPD mortality is highest, leading to one death every two hours.

According to the authors of the study, the early detection of susceptibility genes associated with the development of strategies to prevent smoking in the population at risk are teenagers carrying these genes can be effective on the long term in terms of reducing the prevalence of asthma in Scotland. There is however no further tool for detecting these genes.