ABSTRACT
Background: Smoking behavior is influenced by both genetic and environmental factors. Nicotine is the major addictive substance in cigarettes. Nicotinic acetylcholine receptors [nAChRs] are thought to play an important role in nicotine addiction of smokers. One of the genes, alpha-4 subunit of nicotinic acetylcholine receptor [CHRNA4] gene was reported to be associated with smoking behavior in many populations
Aim: The aim of this study is to determine association between alpha-4 subunit of nicotinic acetylcholine receptor single nucleotide polymorphism [rs2236196 and rs2273502 loci] and smoking behavior among Malay Males
Methods: The study was conducted in Malay smokers [n = 248] and non-smoking controls [n = 248]. DNA was extracted from leucocytes and the two SNPs were determined by a polymerase chain reaction-restriction fragment length polymorphism [PCR-RFLP] method. The PCR product was digested with restriction enzymes AfeI and Sau96I, respectively
Results and conclusion: We found that the AA genotype frequency for CHRNA4 rs2236196 polymorphism in the smoker group was 80.6% while in nonsmoker 77.0%. No mutation [GG genotype] was detected in both groups. The AG genotype for the smoker group was 19.4% while in the nonsmoker group 23.0%. There was no significant difference observed in the genotype [X[2] = 5.106, p = 0.078] and allele frequencies between both study groups. On the other hand, no mutation of CHRNA4 rs2273502 [TT genotype] was detected in the non-smoker group while the frequencies of genotype CC and heterozygous CT in non-smokers were 75.8% and 24.2%, respectively. In the smoker group, the frequencies were 73.4%, 2.0% and 24.6%, for TT, CC and CT, respectively. There was no significant difference observed in rs2273502 [X[2] = 5.16, p = 0.078] and smoking behavior of the subjects. In conclusion, the results revealed that CHRNA4 rs2273502 and rs2236196 gene polymorphisms are not statistically significantly associated with smoking behavior in our population