Scientists believe they have identified a gene that makes some young smokers greatly at risk to nicotine addiction, a factor that also influences the outcome of efforts to wean them off tobacco. The finger is being pointed at two variants of a gene called CYP2A6, which controls enzymes that clear up nicotine in the liver. Variants of this gene decrease levels of the enzymes, which means the nicotine is processed more slowly. As a result, the brain is quickly exposed to high concentrations of nicotine, thus giving the smoker a pleasurable feeling, which is the key to addiction, according to the study, which appears on Tuesday in a British journal, Tobacco Control. Canadian researchers enrolled nearly 1 300 13-year-olds in Quebec, who gave details about their smoking habits. Of these 281 were identified as smokers. They gave a blood sample that was tested for the CYP2A6 gene and the variants.
