Genetic Polymorphism Linked to Nicotine Addiction

Researchers have identified a specific genetic polymorphism linked to the metabolism of nicotine that may act to inhibit smokers from quitting but paradoxically also protects against the development of pulmonary emphysema.

Investigators at Keio University (Tokyo, Japan) obtained DNA samples from a group of 203 current or ex-smokers with suspected chronic obstructive pulmonary disease (COPD) and from a control group of 123 healthy non-smokers. Basic lifestyle information, including the number of cigarettes consumed per day, the duration of smoking, and the time elapsed since quitting was compiled. Then CYP2A6 genotypes were determined for all participants.

The results, published in the July 2003 issue of Thorax, revealed that those carrying the CYP2A6del allele seemed to be inhibited from breaking the smoking habit, but that the allele also seemed to protect them against the development of pulmonary emphysema. The percentage of subjects with a CYP2A6del allele was lower in heavy smokers than in light smokers or non-smokers. It was also lower in ex-smokers than in current smokers.

The authors conclude, "These findings suggest that determination of the genotype will be useful in efficiently withdrawing patients from nicotine dependence in smoking cessation protocols with nicotine containing materials, and will give a new insight into the pathogenesis of smoking induced pulmonary emphysema.”




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