Among Caucasians, an additional defective and frequently distributed allele (CYP2A6*3) has been suggested to play a protective role against nicotine addiction and cigarette consumption.
However, sequence variations in CHRNB2 have not been reported, and its role in influencing human smoking behavior and nicotine dependence is not known.
Further research is needed in order to improve our understanding of how genetic variation in CYP2A6 alters the risk for nicotine dependence and lowers nicotine consumption.
Nicotine dependence criteria were assessed using the NIMH-DIS revised interview and diagnosed according to the DSM-III-R. Familial smoking characteristics were assessed by subject report.
Although the power of the association study was low among some subgroups, the CYP2E1*1D genotype (subjects with at least one variant allele) was associated with alcohol as well as nicotine dependence.
Dysfunction of nAChR has been linked to a number of human diseases such as schizophrenia, Alzheimer's and Parkinson's diseases. nAChRs also play a significant role in nicotine addiction, which is a major public health concern.
Bupropion is a weak dopamine reuptake inhibitor, and individual genetic variation in the dopamine D2 receptor has been associated with nicotine dependence in case-control studies.
Although these findings are preliminary and need validation, the results suggest that a polymorphism in the SLC6A3 may play important roles in smoking onset, and there may be an interactive effect between the SLC6A3 and early smoking onset on modulating the susceptibility of nicotine dependence.
We studied six single-nucleotide polymorphisms (SNPs) in the CHRNA4 gene and four SNPs in the CHRNB2 gene with respect to nicotine dependence in a collection of 901 subjects (815 siblings and 86 parents) from 222 nuclear families with multiple nicotine-addicted siblings.
Case control studies in adults suggest that defective alleles in the gene that codes for the hepatic cytochrome P450 2A6 (CYP2A6) protect against nicotine dependence (ND) and higher levels of cigarette consumption.
Case control studies in adults suggest that defective alleles in the gene that codes for the hepatic cytochrome P450 2A6 (CYP2A6) protect against nicotine dependence (ND) and higher levels of cigarette consumption.
The polymorphism in HTR2A (102T/C, -1438A/G) was identified by means of the polymerase chain reaction followed by restriction fragment length polymorphism, and the Fagerstrom Test for Nicotine Dependence was used to determine the extent of smoking behavior.