Endocannabinoid receptor 1 gene variations increase risk for obesity and modulate body mass index in European populations.

CNRS 8090-Institute of Biology, Pasteur Institute, Lille, France.
Human Molecular Genetics (Impact Factor: 6.68). 08/2008; 17(13):1916-21. DOI: 10.1093/hmg/ddn089
Source: PubMed

ABSTRACT The therapeutic effects of cannabinoid receptor blockade on obesity-associated phenotypes underline the importance of the endocannabinoid pathway on the energy balance. Using a staged-approach, we examined the contribution of the endocannabinoid receptor 1 gene (CNR1) on obesity and body mass index (BMI) in the European population. With the input of CNR1 exons and 3' and 5' regions sequencing and HapMap database, we selected and genotyped 26 tagging single-nucleotide polymorphisms (SNPs) in 1932 obese cases and 1173 non-obese controls of French European origin. Variants that showed significant associations (P < 0.05) with obesity after correction for multiple testing were further tested in two additional European cohorts including 2645 individuals. For the identification of the potential causal variant(s), we further genotyped SNPs in high linkage disequilibrium (LD) with the obesity-associated variants. Of the 25 successfully genotyped CNR1 SNPs, 12 showed nominal evidence of association with childhood obesity, class I and II and/or class III adult obesity (1.16 < OR < 1.40, 0.00003 < P < 0.04). Intronic SNPs rs806381 and rs2023239, which resisted correction for multiple testing were further associated with higher BMI in both Swiss obese subjects and Danish individuals. The genotyping of all know variants in partial LD (r(2) > 0.5) with these two SNPs in the initial case-control study, identified two better associated SNPs (rs6454674 and rs10485170). Our study of 5750 subjects shows that CNR1 variations increase the risk for obesity and modulate BMI in our European population. As CB1 is a drug target for obesity, a pharmacogenetic analysis of the endocannabinoid blockade obesity treatment may be of interest to identify best responders.

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    ABSTRACT: Context. Polycystic ovary syndrome (PCOS) is frequently associated with nonalcoholic fatty liver disease (NAFLD). The endocannabinoid system may play a crucial role in the pathogenesis of NAFLD. Polymorphism of the cannabinoid receptor 1 gene (CNR1) may be responsible for individual susceptibility to obesity and related conditions. Objective. To determine the role of genetic variants of CNR1 in the etiopathology of NAFLD in women with PCOS. Design and Setting. Our department (a tertiary referral center) conducted a cross-sectional, case-controlled study. Subjects. 173 women with PCOS (aged 20-35) and 125 healthy, age- and weight-matched controls were studied. Methods. Hepatic steatosis was assessed by ultrasound evaluation. Single nucleotide polymorphisms of CNR1 (rs806368, rs12720071, rs1049353, rs806381, rs10485170, rs6454674) were genotyped. Results. Frequency of the G allele of rs806381 (P < 0.025) and the GG genotype of rs10485170 (P < 0.03) was significantly higher in women with PCOS and NAFLD than in PCOS women without NAFLD. Frequency of the TT genotype of rs6454674 was higher in PCOS women with NAFLD (not significantly, P = 0.059). In multivariate stepwise regression, allele G of rs806381 was associated with PCOS + NAFLD phenotype. Conclusion. Our preliminary results suggest the potential role of CNR1 polymorphisms in the etiology of NAFLD, especially in PCOS women.
    International Journal of Endocrinology 07/2014; 2014:232975. DOI:10.1155/2014/232975 · 1.52 Impact Factor
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    ABSTRACT: Introduction: Polycystic ovary syndrome (PCOS) is associated with an increasing number of metabolic comorbidities. About 50% of PCOS patients are obese, and insulin resistance affects up to 70% of these women. The endocannabinoid system contributes to human energy homeostasis. CNR1 is a biological candidate for human obesity and related metabolic disorders. The aim of this study was to determine the relationships between CNR1 polymorphisms and anthropometric and metabolic parameters in PCOS women. Material and methods: 130 women diagnosed with PCOS according to the Rotterdam criteria were recruited. The control group consisted of 70 healthy women. Medical history was taken, and physical examination as well as assessment of anthropometric (body mass, height, waist and hip circumference, BMI, waist-to-hip ratio [WHR]) and metabolic parameters (glucose and insulin, the insulin resistance index HOMA, lipid profile) was carried out. Genetic studies to detect six CNR1 gene polymorphisms were performed. Results: The total cholesterol and low-density lipoprotein (LDL) cholesterol levels in PCOS women carrying T/T genotype of rs2023239 CNR1 polymorphism were higher than in those with C/T and C/C. There were no statistical differences in other metabolic parameters or in the value of BMI and WHR between the variants of rs2023239 CNR1 polymorphism. The other studied polymorphisms of the CNR1 gene were not associated with anthropometric or metabolic parameters in PCOS women. There were no differences in anthropometric or metabolic parameters between the variants of studied polymorphisms of the CNR1 gene in control women. Conclusions: On the basis of our study, it seems that CNR1 polymorphisms are not associated with obesity and metabolic disorders, including insulin resistance, in PCOS women.
    Endokrynologia Polska 01/2014; 65(3):181-8. DOI:10.5603/EP.2014.0025 · 1.21 Impact Factor
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