Background: Genetic and metabolic factors associated with nicotine metabolism may be related to smoking behavior. Aim: To assess the prevalence of allelic and genotype variants of CYP2A6 in a sample of Chilean subjects and to evaluate their relationship with smoking and tobacco dependence. Material and Methods: The genotype frequencies for *2, *3 and *4 of CYP2A6*1 (wild type) gene were determined by polymerase chain reaction (PCR) in 54 volunteers. Addiction to tobacco was evaluated using the Fagerstrom Test. The association between the presence of allelic variants of CYP2A6 and smoking and tobacco dependence was evaluated with chi square test. Results: The prevalence of *1, *2 (wt/*2), *3 (wt/*3 or *31*3) and *4 (del/del) were 92.6%, 3.7%, 0% y 3.7%, respectively. No significant association was observed between being a carrier of a variant genotype of CYP2A6 and smoking or tobacco dependence. Conclusions: In this sample of Chilean individuals we did not find a relation between any CYP2A6 genotype with smoking or tobacco dependence.

CYP2E1 enzyme is related to nonalcoholic steatohepatitis (NASH) due to its ability for reactive oxygen species production, which can be influenced by polymorphisms in the gene. The aim of this study was to investigate hepatic levels, activity, and polymorphisms of the CYP2E1 gene to correlate it with clinical and histological features in 48 female obese NASH patients. Subjects were divided into three groups: (i) normal; (ii) steatosis; and (iii) steatohepatitis. CYP2E1 protein level was assayed in microsomes from liver biopsies, and in vivo chlorzoxazone hydroxylation was determined by HPLC. Genomic DNA was isolated for genotype analysis through PCR. The results showed that liver CYP2E1 content was significantly higher in the steatohepatitis (45%; p=0.024) and steatosis (22%; p=0.032) group compared with normal group. Chlorzoxazone hydroxylase activity showed significant enhancement in the steatohepatitis group (15%, p=0.027) compared with the normal group. c2 rare allele of RsallPstl polymorphisms but no C allele of Dral polymorphism was positively associated with CHZ hydroxylation, which in turn is correlated with liver CYP2E1 content (r=0.59; p=0.026). In conclusion, c2 allele is positively associated with liver injury in NASH. This allele may determine a higher transcriptional activity of the gene, with consequent enhancement in pro-oxidant activity of CYP2E1 thus affording liver toxicity