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Marcin Wojnar - One of the best experts on this subject based on the ideXlab platform.
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The CC genotype in the T102C HTR2A polymorphism predicts relapse in individuals after alcohol treatment.
Journal of psychiatric research, 2013Co-Authors: Andrzej Jakubczyk, Małgorzata Wrzosek, Anna Klimkiewicz, Halina Matsumoto, Kirk J. Brower, Margit Burmeister, Maciej Kopera, Aleksandra Krasowska, Marcin WojnarAbstract:The serotonin system is hypothesized to contribute to predisposition and course of alcohol dependence. However, the potential association between the T102C polymorphism (Rs6313) in the type 2A serotonin receptor (HTR2A) gene and treatment outcomes in alcohol dependence has not been investigated. The aim of the study was to assess the contribution of this genetic polymorphism as a predictor of relapse in relation to other previously identified predictors. A sample of 254 alcohol dependent subjects, were recruited in alcohol treatment centers in Warsaw, Poland and prospectively assessed at baseline and follow-up after 12 months. At baseline, information about demographics, psychopathological symptoms and alcohol problems was obtained. The stop-signal task was performed and blood samples for genetic analysis of HTR2A T102C (Rs6313) were collected. Relapse was defined as any drinking during the follow-up period. The statistical analysis showed that the CC genotype was significantly associated with increased relapse. Other significant factors were baseline depressive symptoms, number of drinking days during the 3 months prior to the baseline assessment, severity of alcohol-related problems, and a lifetime history of impulsive suicide attempts. Logistic regression analysis with and without the genetic factor revealed that adding the genetic factor increased the R square value by about 4%, with the CC genotype in the T102C polymorphism being the strongest predictor of relapse (OR = 2.32). The significant influence on relapse of the CC genotype, which is associated with fewer 5-HT2A receptors in the central nervous system, suggests the possibility that this genetic polymorphism could influence response to serotonergic medications.
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The CC genotype in HTR2A T102C polymorphism is associated with behavioral impulsivity in alcohol-dependent patients.
Journal of psychiatric research, 2011Co-Authors: Andrzej Jakubczyk, Małgorzata Wrzosek, Jacek Łukaszkiewicz, Halina Matsumoto, Kirk J. Brower, Joanna Sadowska-mazuryk, Elżbieta Śliwerska, Jennifer M. Glass, Margit Burmeister, Marcin WojnarAbstract:High levels of impulsivity can increase the vulnerability for development of alcohol dependence. Moreover, impulsivity is considered to be a predictor of poor treatment outcomes. Few studies, however, have directly examined the genetics of impulsivity in alcohol-dependent patients. We analyzed the relationships between a well-recognized genetic marker of serotonin activity and levels of impulsivity as measured by both the Barratt Impulsiveness Scale (BIS-11) and the stop-signal task among 304 alcohol-dependent patients. The stop-signal task was used as an independent, objective method of estimating the level of behavioral impulsivity, and the BIS-11 as a self-report measure of global impulsivity. Blood was collected and analyzed for the T102C (Rs6313) polymorphism in the serotonin type 2A receptor gene (HTR2A). Our results indicate a significant association between high levels of behavioral impulsivity and the C/C genotype of Rs6313 in alcohol-dependent patients. The CC genotype has been previously found to be associated with a reduction in 5HT2A receptors in the central nervous system. These results support the hypothesis that genetic factors are important determinants of behavioral impulsivity in alcohol-dependent patients, and that the serotonin system plays an important role in establishing its level.
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Association of polymorphisms in HTR2A, HTR1A and TPH2 genes with suicide attempts in alcohol dependence: A preliminary report
Psychiatry research, 2011Co-Authors: Małgorzata Wrzosek, Jacek Łukaszkiewicz, Piotr Serafin, Andrzej Jakubczyk, Anna Klimkiewicz, Halina Matsumoto, Kirk J. Brower, Marcin WojnarAbstract:We investigated a relationship between selected polymorphisms: Rs6313 in HTR2A, rs6295 in HTR1A and rs1386494 in TPH2, and suicidal behaviour in 150 alcohol-dependent patients. There was a significant association between more frequent C102C genotype in HTR2A and suicide attempts in alcoholic females. No differences in genotype distribution in HTR1A and TPH2 SNPs were found between patients with and without suicide attempts.
Thelma Beatriz González-castro - One of the best experts on this subject based on the ideXlab platform.
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Genetic association analysis of 5-HTR2A gene variants in eating disorders in a Mexican population.
Brain and behavior, 2019Co-Authors: Alma Delia Genis-mendoza, David Ruiz-ramos, María Lilia López-narváez, Carlos Alfonso Tovilla-zárate, Ana Rosa García, Gabriela Cortes Meda, José Jaime Martínez-magaña, Thelma Beatriz González-castro, Isela Esther Juárez-rojop, Humberto NicoliniAbstract:INTRODUCTION The 5-HTR2A gene has been implicated as candidate gene for eating disorders. The aim of the present study was to analyze the association of rs6311 and Rs6313 polymorphisms of 5-HTR2A gene with eating disorders in Mexican population, and to evaluate if the polymorphisms of 5-HTR2A gene were associated with comorbidities in eating behavior. METHODS We conducted a case-control analysis with 460 subjects. We included 168 patients with eating disorders and 292 controls; two polymorphisms of 5-HTR2A gene were genotyped. We assessed the association by allele, genotype, and inheritance models. Psychiatric comorbidities were analyzed by genotype in patients with eating disorders. RESULTS We found an association between rs6311 and eating disorders in a Mexican population by allele (OR = 8.09; 95% CI = 5.99-11.03; p = 2.2e-16) and genotype (OR = 76.14; 95% CI = 35.61-177.18; p = 2.2e-16). Individuals who carried GG genotype showed increased risk for suicide attempted (OR = 2.14; CI = 1.10-4.26; p = 0.035) as comorbidity associated with eating disorders. No positive associations were observed for Rs6313 polymorphism. CONCLUSION Our results showed an association of rs6311 (A1438G) polymorphism of 5-HTR2A gene with eating disorders, and these polymorphic variants could increase the risk of psychiatric comorbidities. However, more studies are required to replicate the results and to reach to a conclusive association between eating disorders and rs6311.
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Association of the 5HTR2A gene with suicidal behavior: CASE-control study and updated meta-analysis
BMC Psychiatry, 2013Co-Authors: Thelma Beatriz González-castro, Humberto Nicolini, Carlos Tovilla-zárate, Isela Juárez-rojop, Sherezada Pool García, Martha Patricia Velázquez-sánchez, Alma Genis, Lilia López NarváezAbstract:Background The polymorphism Rs6313 (T102C) has been associated with suicidal behavior in case–control and meta-analysis studies, but results and conclusions remain controversial. The aim of the present study was to examine the association between T102C with suicidal behavior in a case–control study and, to assess the combined evidence – this case–control study and available data from other related studies – we carried out a meta-analysis. Methods We conducted a case–control study that included 161 patients with suicide attempts and 244 controls; we then performed a meta-analysis. The following models were evaluated in the meta-analysis: A) C allele vs T allele; B) T allele vs C allele; C) Caucasian population, D) Asian population, and E) suicide attempters with schizophrenia. Results We found an association between attempted suicide and control participants for genotype (χ2=6.28, p=0.04, df=2) and allele (χ2=6.17, p=0.01, df=1, OR 1.48 95% IC: 1.08-2.03) frequencies in the case–control study. The meta-analysis, comprising 23 association studies (including the present one), showed that the Rs6313 polymorphism is not associated with suicidal behavior for the following comparisons:T allele vs C allele (OR: 1.03; 95% CI 0.93-1.13; p(Z)=0.44); C allele vs T allele: (OR:0.99; 95% CI: 0.90-1.08; p(Z)=0.22); Caucasians (OR:1.09; 95% CI: 0.96-1.23), and Asians (OR:0.96; 95% CI: 0.84-1.09). Conclusion Our results showed association between the Rs6313 (T102C) polymorphism and suicidal behavior in the case–control study. However, the meta-analysis showed no evidence of association. Therefore, more studies are necessary to determine conclusively an association between T102C and suicidal behavior.
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Association of the 5HTR2A gene with suicidal behavior: CASE-control study and updated meta-analysis
BMC psychiatry, 2013Co-Authors: Thelma Beatriz González-castro, Carlos Alfonso Tovilla-zárate, Isela Esther Juárez-rojop, Humberto Nicolini, Martha Patricia Velázquez-sánchez, Alma Genis, Sherezada Pool García, Lilia López NarváezAbstract:The polymorphism Rs6313 (T102C) has been associated with suicidal behavior in case–control and meta-analysis studies, but results and conclusions remain controversial. The aim of the present study was to examine the association between T102C with suicidal behavior in a case–control study and, to assess the combined evidence – this case–control study and available data from other related studies – we carried out a meta-analysis. We conducted a case–control study that included 161 patients with suicide attempts and 244 controls; we then performed a meta-analysis. The following models were evaluated in the meta-analysis: A) C allele vs T allele; B) T allele vs C allele; C) Caucasian population, D) Asian population, and E) suicide attempters with schizophrenia. We found an association between attempted suicide and control participants for genotype (χ2=6.28, p=0.04, df=2) and allele (χ2=6.17, p=0.01, df=1, OR 1.48 95% IC: 1.08-2.03) frequencies in the case–control study. The meta-analysis, comprising 23 association studies (including the present one), showed that the Rs6313 polymorphism is not associated with suicidal behavior for the following comparisons:T allele vs C allele (OR: 1.03; 95% CI 0.93-1.13; p(Z)=0.44); C allele vs T allele: (OR:0.99; 95% CI: 0.90-1.08; p(Z)=0.22); Caucasians (OR:1.09; 95% CI: 0.96-1.23), and Asians (OR:0.96; 95% CI: 0.84-1.09). Our results showed association between the Rs6313 (T102C) polymorphism and suicidal behavior in the case–control study. However, the meta-analysis showed no evidence of association. Therefore, more studies are necessary to determine conclusively an association between T102C and suicidal behavior.
Małgorzata Wrzosek - One of the best experts on this subject based on the ideXlab platform.
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The CC genotype in the T102C HTR2A polymorphism predicts relapse in individuals after alcohol treatment.
Journal of psychiatric research, 2013Co-Authors: Andrzej Jakubczyk, Małgorzata Wrzosek, Anna Klimkiewicz, Halina Matsumoto, Kirk J. Brower, Margit Burmeister, Maciej Kopera, Aleksandra Krasowska, Marcin WojnarAbstract:The serotonin system is hypothesized to contribute to predisposition and course of alcohol dependence. However, the potential association between the T102C polymorphism (Rs6313) in the type 2A serotonin receptor (HTR2A) gene and treatment outcomes in alcohol dependence has not been investigated. The aim of the study was to assess the contribution of this genetic polymorphism as a predictor of relapse in relation to other previously identified predictors. A sample of 254 alcohol dependent subjects, were recruited in alcohol treatment centers in Warsaw, Poland and prospectively assessed at baseline and follow-up after 12 months. At baseline, information about demographics, psychopathological symptoms and alcohol problems was obtained. The stop-signal task was performed and blood samples for genetic analysis of HTR2A T102C (Rs6313) were collected. Relapse was defined as any drinking during the follow-up period. The statistical analysis showed that the CC genotype was significantly associated with increased relapse. Other significant factors were baseline depressive symptoms, number of drinking days during the 3 months prior to the baseline assessment, severity of alcohol-related problems, and a lifetime history of impulsive suicide attempts. Logistic regression analysis with and without the genetic factor revealed that adding the genetic factor increased the R square value by about 4%, with the CC genotype in the T102C polymorphism being the strongest predictor of relapse (OR = 2.32). The significant influence on relapse of the CC genotype, which is associated with fewer 5-HT2A receptors in the central nervous system, suggests the possibility that this genetic polymorphism could influence response to serotonergic medications.
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The CC genotype in HTR2A T102C polymorphism is associated with behavioral impulsivity in alcohol-dependent patients.
Journal of psychiatric research, 2011Co-Authors: Andrzej Jakubczyk, Małgorzata Wrzosek, Jacek Łukaszkiewicz, Halina Matsumoto, Kirk J. Brower, Joanna Sadowska-mazuryk, Elżbieta Śliwerska, Jennifer M. Glass, Margit Burmeister, Marcin WojnarAbstract:High levels of impulsivity can increase the vulnerability for development of alcohol dependence. Moreover, impulsivity is considered to be a predictor of poor treatment outcomes. Few studies, however, have directly examined the genetics of impulsivity in alcohol-dependent patients. We analyzed the relationships between a well-recognized genetic marker of serotonin activity and levels of impulsivity as measured by both the Barratt Impulsiveness Scale (BIS-11) and the stop-signal task among 304 alcohol-dependent patients. The stop-signal task was used as an independent, objective method of estimating the level of behavioral impulsivity, and the BIS-11 as a self-report measure of global impulsivity. Blood was collected and analyzed for the T102C (Rs6313) polymorphism in the serotonin type 2A receptor gene (HTR2A). Our results indicate a significant association between high levels of behavioral impulsivity and the C/C genotype of Rs6313 in alcohol-dependent patients. The CC genotype has been previously found to be associated with a reduction in 5HT2A receptors in the central nervous system. These results support the hypothesis that genetic factors are important determinants of behavioral impulsivity in alcohol-dependent patients, and that the serotonin system plays an important role in establishing its level.
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Association of polymorphisms in HTR2A, HTR1A and TPH2 genes with suicide attempts in alcohol dependence: A preliminary report
Psychiatry research, 2011Co-Authors: Małgorzata Wrzosek, Jacek Łukaszkiewicz, Piotr Serafin, Andrzej Jakubczyk, Anna Klimkiewicz, Halina Matsumoto, Kirk J. Brower, Marcin WojnarAbstract:We investigated a relationship between selected polymorphisms: Rs6313 in HTR2A, rs6295 in HTR1A and rs1386494 in TPH2, and suicidal behaviour in 150 alcohol-dependent patients. There was a significant association between more frequent C102C genotype in HTR2A and suicide attempts in alcoholic females. No differences in genotype distribution in HTR1A and TPH2 SNPs were found between patients with and without suicide attempts.
Humberto Nicolini - One of the best experts on this subject based on the ideXlab platform.
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Genetic association analysis of 5-HTR2A gene variants in eating disorders in a Mexican population.
Brain and behavior, 2019Co-Authors: Alma Delia Genis-mendoza, David Ruiz-ramos, María Lilia López-narváez, Carlos Alfonso Tovilla-zárate, Ana Rosa García, Gabriela Cortes Meda, José Jaime Martínez-magaña, Thelma Beatriz González-castro, Isela Esther Juárez-rojop, Humberto NicoliniAbstract:INTRODUCTION The 5-HTR2A gene has been implicated as candidate gene for eating disorders. The aim of the present study was to analyze the association of rs6311 and Rs6313 polymorphisms of 5-HTR2A gene with eating disorders in Mexican population, and to evaluate if the polymorphisms of 5-HTR2A gene were associated with comorbidities in eating behavior. METHODS We conducted a case-control analysis with 460 subjects. We included 168 patients with eating disorders and 292 controls; two polymorphisms of 5-HTR2A gene were genotyped. We assessed the association by allele, genotype, and inheritance models. Psychiatric comorbidities were analyzed by genotype in patients with eating disorders. RESULTS We found an association between rs6311 and eating disorders in a Mexican population by allele (OR = 8.09; 95% CI = 5.99-11.03; p = 2.2e-16) and genotype (OR = 76.14; 95% CI = 35.61-177.18; p = 2.2e-16). Individuals who carried GG genotype showed increased risk for suicide attempted (OR = 2.14; CI = 1.10-4.26; p = 0.035) as comorbidity associated with eating disorders. No positive associations were observed for Rs6313 polymorphism. CONCLUSION Our results showed an association of rs6311 (A1438G) polymorphism of 5-HTR2A gene with eating disorders, and these polymorphic variants could increase the risk of psychiatric comorbidities. However, more studies are required to replicate the results and to reach to a conclusive association between eating disorders and rs6311.
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Association of the 5HTR2A gene with suicidal behavior: CASE-control study and updated meta-analysis
BMC Psychiatry, 2013Co-Authors: Thelma Beatriz González-castro, Humberto Nicolini, Carlos Tovilla-zárate, Isela Juárez-rojop, Sherezada Pool García, Martha Patricia Velázquez-sánchez, Alma Genis, Lilia López NarváezAbstract:Background The polymorphism Rs6313 (T102C) has been associated with suicidal behavior in case–control and meta-analysis studies, but results and conclusions remain controversial. The aim of the present study was to examine the association between T102C with suicidal behavior in a case–control study and, to assess the combined evidence – this case–control study and available data from other related studies – we carried out a meta-analysis. Methods We conducted a case–control study that included 161 patients with suicide attempts and 244 controls; we then performed a meta-analysis. The following models were evaluated in the meta-analysis: A) C allele vs T allele; B) T allele vs C allele; C) Caucasian population, D) Asian population, and E) suicide attempters with schizophrenia. Results We found an association between attempted suicide and control participants for genotype (χ2=6.28, p=0.04, df=2) and allele (χ2=6.17, p=0.01, df=1, OR 1.48 95% IC: 1.08-2.03) frequencies in the case–control study. The meta-analysis, comprising 23 association studies (including the present one), showed that the Rs6313 polymorphism is not associated with suicidal behavior for the following comparisons:T allele vs C allele (OR: 1.03; 95% CI 0.93-1.13; p(Z)=0.44); C allele vs T allele: (OR:0.99; 95% CI: 0.90-1.08; p(Z)=0.22); Caucasians (OR:1.09; 95% CI: 0.96-1.23), and Asians (OR:0.96; 95% CI: 0.84-1.09). Conclusion Our results showed association between the Rs6313 (T102C) polymorphism and suicidal behavior in the case–control study. However, the meta-analysis showed no evidence of association. Therefore, more studies are necessary to determine conclusively an association between T102C and suicidal behavior.
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Association of the 5HTR2A gene with suicidal behavior: CASE-control study and updated meta-analysis
BMC psychiatry, 2013Co-Authors: Thelma Beatriz González-castro, Carlos Alfonso Tovilla-zárate, Isela Esther Juárez-rojop, Humberto Nicolini, Martha Patricia Velázquez-sánchez, Alma Genis, Sherezada Pool García, Lilia López NarváezAbstract:The polymorphism Rs6313 (T102C) has been associated with suicidal behavior in case–control and meta-analysis studies, but results and conclusions remain controversial. The aim of the present study was to examine the association between T102C with suicidal behavior in a case–control study and, to assess the combined evidence – this case–control study and available data from other related studies – we carried out a meta-analysis. We conducted a case–control study that included 161 patients with suicide attempts and 244 controls; we then performed a meta-analysis. The following models were evaluated in the meta-analysis: A) C allele vs T allele; B) T allele vs C allele; C) Caucasian population, D) Asian population, and E) suicide attempters with schizophrenia. We found an association between attempted suicide and control participants for genotype (χ2=6.28, p=0.04, df=2) and allele (χ2=6.17, p=0.01, df=1, OR 1.48 95% IC: 1.08-2.03) frequencies in the case–control study. The meta-analysis, comprising 23 association studies (including the present one), showed that the Rs6313 polymorphism is not associated with suicidal behavior for the following comparisons:T allele vs C allele (OR: 1.03; 95% CI 0.93-1.13; p(Z)=0.44); C allele vs T allele: (OR:0.99; 95% CI: 0.90-1.08; p(Z)=0.22); Caucasians (OR:1.09; 95% CI: 0.96-1.23), and Asians (OR:0.96; 95% CI: 0.84-1.09). Our results showed association between the Rs6313 (T102C) polymorphism and suicidal behavior in the case–control study. However, the meta-analysis showed no evidence of association. Therefore, more studies are necessary to determine conclusively an association between T102C and suicidal behavior.
Gloria Pérez-rubio - One of the best experts on this subject based on the ideXlab platform.
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Data on genotype frequency for SNPs associated to age of smoking onset and successful smoking cessation treatment.
Data in brief, 2019Co-Authors: Gloria Pérez-rubio, Luis Alberto López-flores, Alejandra Ramírez-venegas, Raúl H Sansores, Ramcés Falfán-valenciaAbstract:Abstract This article contains data on the allele and genotype frequency for single nucleotide polymorphisms (SNPs) in candidate genes CHRNA5 (rs16969968, rs17408276, rs680244) CHRNA3 (rs6495307, rs12914385) NRXN1 (rs10865246, rs1882296, rs985919) and HTR2A (rs6311, Rs6313) previously evaluated as genetic risk variants for cigarette smoking at an early age and relapse to smoking cessation treatment Perez-Rubio et al., 2018. These SNPs were selected due to previous associations in other populations, including Mexican Mestizos. Smokers were classified according to the age at onset, cigarettes per day, nicotine dependence, COPD status and therapy received.
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Genetic variants as risk factors for cigarette smoking at an early age and relapse to smoking cessation treatment: A pilot study.
Gene, 2019Co-Authors: Gloria Pérez-rubio, Luis Alberto López-flores, Enrique Ambrocio-ortiz, Salvador García-carmona, Leonor García-gómez, Valeri Noé-díaz, Karol J. Nava-quiroz, Fernando Morales-gonzález, Alma D. Del Angel-pablo, Alejandra Ramírez-venegasAbstract:Abstract Objectives Tobacco smoking is a complex and multifactorial disease involving both environmental and genetic factors. In the Mexican mestizo population, single-nucleotide polymorphisms (SNPs) associated with cigarette smoking and a greater degree of nicotine addiction have been identified; however, no possible roles have been explored in regard to the age of onset of smoking or in the success of quitting. Methods In this study, 151 Mexican mestizo, who smoke cigarettes, were included. They were grouped according to the age at which they started smoking: those who started smoking before 18 years of age (early smokers, ES) and those who started smoking ≥18 years of age (late smokers, LS). In addition, relapse in smoking was evaluated at the first month after the end of treatment. Genetic association was evaluated characterizing 10 SNPs in 4 genes (CHRNA5, CHRNA3, NRXN1, and HTR2A). Results According to the dominant model of genetic inheritance, Rs6313 (CT+TT) of the HTR2A gene was associated (p = 0.0201) with cigarette consumption at early ages (OR = 2.68, CI = 1.18–6.07). When the risk of relapse was analyzed one month after the end of treatment, regardless of the age of onset, the T allele (Rs6313) of HTR2A appeared to be a risk factor for relapse (OR = 2.92, 95% CI = 1.06–8.11); the T allele was found more frequently in those who relapsed (50.0%) compared with people who maintained abstinence (25.4%) (p = 0.0332). Conclusions Our findings suggest that in Mexican mestizos who smoke cigarettes, the presence of the T allele in Rs6313 of the HTR2A gene increases the risk for the early onset of cigarette smoking as well as the risk for relapsing one month after completing smoking cessation treatment.
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Polymorphisms in HTR2A and DRD4 Predispose to Smoking and Smoking Quantity.
PloS one, 2017Co-Authors: Gloria Pérez-rubio, Luis Alberto López-flores, Alejandra Ramírez-venegas, Valeri Noé Díaz, Leonor García Gómez, Karina Elvira Fabián, Salvador García Carmona, Enrique Ambrocio-ortiz, Rocío Contreras Romero, Noé Alcantar-ayalaAbstract:Background Genes encoding the receptors involved in the dopaminergic and serotonergic pathways are potential candidates in the mechanisms of nicotine addiction. Aims To identify genetic variants in the promoter regions and exons of the DRD4 and HTR2A genes associated with tobacco smoking and the degree of nicotine addiction in Mexican mestizos. Methods The study included 438 non-smokers (NS) and 1,157 current smokers, ranked based on their consumption of cigarettes per day (cpd): 574 heavy smokers (HS, >20 cpd) and 583 light smokers (LS, 1–10 cpd). Genotyping was performed for 4 and 8 single nucleotide polymorphisms (SNPs) in the DRD4 and HTR2A genes, respectively. Results The C allele of rs1800955 in DRD4 was found to be associated with cigarette smoking in the HS vs. NS and LS vs. NS comparisons (p = 2.34E-03 and p = 1.13E-03, respectively); the association was maintained in the homozygous CC genotype (p = 5.00E-04 and p = 2.00E-04, respectively). The T allele of Rs6313 in HTR2A was significantly associated with cigarette smoking and a greater degree of nicotine addiction (p = 4.77E-03, OR = 1.55); the association was maintained in the homozygous genotype (TT) (p = 4.90E-03, OR = 1.96). The A allele of Rs6313 was associated with cigarette smoking in the HS vs. NS comparison (p = 1.53E-02, OR = 1.36); the risk was nearly doubled in the homozygous AA genotype (p = 1.30E-03, OR = 1.83) compared with the heterozygous GA genotype (OR = 1.38). Conclusions Among Mexican mestizos, the C allele of rs1800955 in the DRD4 gene and the A allele of rs6311 in the HTR2A gene are associated with cigarette smoking, whereas the T allele of Rs6313 in HTR2A is associated with cigarette smoking and the degree of nicotine addiction.
