Faulty gene reduces nicotine addiction risk

Kicking the cigarette habit may soon become much easier following the discovery of a gene that protects against nicotine addiction. More accurately, researchers from the University of Toronto have found that if this "nicotine gene" is faulty, a person is less likely to become addicted to smoking.

Moreover, if a person with a faulty gene becomes addicted, he or she will generally smoke fewer cigarettes and therefore will face a reduced cancer risk from tobacco.

The discovery of this gene's direct link to nicotine addiction opens up new horizons in overcoming the smoking habit. While many smokers enjoy the hands-on aspects of smoking - puffing, flicking ash and having nice lighters - it is actually the nicotine that gets you hooked.

The body deals with nicotine by producing chemicals known as enzymes that can break it down. This enzyme, CYP2A6, is produced by a gene, and when the gene is not right the enzyme it produces cannot handle the nicotine properly.

The work by Dr Rachel F. Tyndale, Dr Michael L. Pianezza and Dr Edward M. Sellers is published this morning in the science journal Nature. They set out to determine how many addicted smokers had this faulty gene and found that very few smokers, about one in 10, had.

They also discovered that the smokers who had the faulty gene did not have to smoke quite as much to satisfy their addiction - 129 cigarettes per week for those with the faulty gene, as against 159 cigarettes per week for those with normal CYP2A6.

The researchers suggested that "inhibiting this enzyme may be a new way to help prevent and treat tobacco smoking.

"Individuals carrying [the faulty gene] may have a decreased risk of developing tobacco-related cancers and other medical complications because they have a decreased risk of becoming a smoker and, if they do become dependent, they smoke less than those without impaired nicotine metabolism," the researchers concluded.