Passive smoking risk influenced by genes

Some children with parents who smoke could have a higher risk of developing asthma due to their genetic make-up, according to a new German study. Researchers at the Children's University in Munich found that children of smokers, who had also inherited an altered version of the glutathione S transferase (GST) gene, were five times more likely to develop asthma, compared to children who did not have the gene variation. They were also three times more likely to have ever wheezed, say the scientists, who published their findings in the journal Thorax. They studied over 3000 German schoolchildren and found that the gene variations had no effect on the asthma risk for children of non-smokers.

The GST gene is one of a number of genes thought to be involved in breaking down tobacco smoke toxins in the body. It seems that inheriting a faulty GST gene can increase the risk of asthma in children, perhaps by reducing their ability to deal with second-hand smoke. 'While environmental tobacco smoke exposure is a serious health hazard for children, some [children] are even more susceptible to developing asthma and severe asthma symptoms when exposed to passive smoking', said lead author Michael Kabesch.

Although the study was large, further work is needed to confirm the link as it included just 11 children who had a GST gene variation and 45 who were exposed to tobacco smoke. However, a spokesman for Asthma UK welcomed the research: 'Important findings such as these should help us to begin to unravel the complex jigsaw of interactions between our genes and factors in the environment that can lead to the development of asthma', he told BBC News Online.