A variant associated with nicotine dependence, lung cancer and peripheral arterial disease

Abstract

With the advent of large genomic data sets, geneticists can examine at a new level the influence of genes on behaviour. Two groups have conducted genome-wide association studies involving lung cancer, and both find that sequences in the nicotinic acetylcholine receptor subunit gene cluster contribute susceptibility, although the groups took different paths to this result. Hung et al. suggest that this susceptibility is not related to smoking status or frequency, and show association with a specific amino acid change. Thorgeirsson et al. find that alleles present in a cluster of nicotinic acid receptor genes do not influence whether or not a person smokes, but do affect the number of cigarettes smoked per day, and are therefore also associated with risk of lung cancer and peripheral arterial disease. Either way, the possible potential of nicotinic acetylcholine receptors as drug targets is underlined. A genome-wide association study involving lung cancer finds that genetic sequences in the nicotinic acetylcholine receptor subunit gene cluster contribute to susceptibility. This paper finds that alleles present in a cluster of nicotinic acid receptor genes affect smoking quantity in European samples, and are therefore also associated with risk of lung cancer and peripheral arterial disease. Smoking is a leading cause of preventable death, causing about 5 million premature deaths worldwide each year1,2. Evidence for genetic influence on smoking behaviour and nicotine dependence (ND)3,4,5,6,7,8 has prompted a search for susceptibility genes. Furthermore, assessing the impact of sequence variants on smoking-related diseases is important to public health9,10. Smoking is the major risk factor for lung cancer (LC)11,12,13,14 and is one of the main risk factors for peripheral arterial disease (PAD)15,16,17. Here we identify a common variant in the nicotinic acetylcholine receptor gene cluster on chromosome 15q24 with an effect on smoking quantity, ND and the risk of two smoking-related diseases in populations of European descent. The variant has an effect on the number of cigarettes smoked per day in our sample of smokers. The same variant was associated with ND in a previous genome-wide association study that used low-quantity smokers as controls18,19, and with a similar approach we observe a highly significant association with ND. A comparison of cases of LC and PAD with population controls each showed that the variant confers risk of LC and PAD. The findings provide a case study of a gene–environment interaction20, highlighting the role of nicotine addiction in the pathology of other serious diseases.