REV-ERB ALPHA mainly inhibits transcription in association with co-repressor NCoR and chromatin remodelling in the element response in the target genes through the recruitment of HDAC3. Studies performed in the knockout mouse models of REV-ERB ALPHA showed a preference for lipid utilization instead of glucose, Sancycline especially during the resting period, in addition to higher levels of glucose due to the misalignment of energy utilization, as well as higher adipose accumulation following a high fat diet. These findings point to the important role of REV-ERB ALPHA in the control of glucose and lipid metabolism. In addition, it actively participates during the differentiation from preadipocytes to adipocytes along with PPARc. Therefore, changes in its expression or disturbances in its regulation due to the presence of Gracillin geneticvariations could be associated with modifications in adipogenesis as well as with misalignments in the circadian expression of metabolic genes that could lead to increase in adiposity and incidence of obesity. We can speculate that the higher frequency of AA in the obese group and its association with higher BMI and waist circumference could alter the expression or the regulation of REV-ERB ALPHA and its target genes. Alternatively, rs939347 could be in linkage disequilibrium with other functional SNPs in the Rev-Erb alpha gene that could affect its regulation. Future studies should be done to investigate this hypothesis. The main limitation of our study is the use of a unique cohort to test SNP rs939347, although our population is not subjected to stratification, as all participants were from Spain. However, it is essential to replicate our results in other populations. Previously, Goumidi et al., did not find any association of rs2071570 with BMI. Nevertheless, as we mentioned before, either the types of cohorts studied or the statistical approximation used differed. On the other hand, we did not obtain any information about sleep duration, or time of the day that could associate this polymorphism with a disruption in the sleep cycles. Obesity is characterized by the accumulation of excessive fat tissue, which may lead to adverse health consequences, such as diabetes, cardiovascular disease, and cancer.