Individual differences in cognitive performance are partly dependent, on genetic polymporhisms. One of the single-nucleotide polymorphisms (SNP) of the CNR1 gene, which codes for cannabinoid receptor 1 (CB1R), is the rs2180619, located in a regulatory region of this gene (6q14-q15). The alleles of the rs2180619 are A > G; the G allele has been associated with addiction and high levels of anxiety (when the G allele interacts with the SS genotype of the 5-HTTLPR gene). However, GG genotype is observed also in healthy subjects. Considering G allele as risk for 'psychopathological conditions', it is possible that GG healthy subjects do not be addicted or anxious, but would have reduced performance, compared to AA subjects, in attentional control and working memory processing. One hundred and sixty-four healthy young Mexican-Mestizo subjects (100 women and 64, men; mean age: 22.86 years, SD=2.72) participated in this study, solving a task where attentional control and working memory were required. GG subjects, compared to AA subjects showed: (1) a general lower performance in the task (P = 0.02); (2) lower performance only when a high load of information was held in working memory (P = 0.02); and (3) a higher vulnerability to distractors (P = 0.03). Our results suggest that, although the performance of GG subjects was at normal levels, a lower efficiency of the endocannabinoid system, probably due to a lowered expression of CB1R, produced a reduction in the performance of these subjects when attentional control and working memory processing is challenged.

TwinsMX is a national twin registry in Mexico recently created with institutional support from the Universidad Nacional Autónoma de México. It aims to serve as a platform to advance epidemiological and genetic research in the country and to disentangle the genetic and environmental contributions to health and disease in the admixed Mexican population. Here, we describe our recruitment and data collection strategies and discuss both the progress to date and future directions. More information about the registry is available on our website: https://twinsmxofficial.unam.mx/ (content in Spanish).

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Individual differences in working memory ability are mainly revealed when a demanding challenge is imposed. Here, we have associated cannabinoid 1 (CB1) receptor genetic variation rs2180619 (AA, AG, GG), which is located in a potential CNR1 regulatory sequence, with performance in working memory. Two-hundred and nine Mexican-mestizo healthy young participants (89 women, 120 men, mean age: 23.26 years, SD = 2.85) were challenged to solve a medium (2-back) vs. a high (3-back) difficulty N-back tasks. All subjects responded as expected, performance was better with the medium than the high demand task version, but no differences were found among genotypes while performing each working memory (WM) task. However, the cost of the level of complexity in N-back paradigm was double for GG subjects than for AA subjects. It is noteworthy that an additive-dosage allele relation was found for G allele in terms of cost of level of complexity. These genetic variation results support that the endocannabinoid system, evaluated by rs2180619 polymorphism, is involved in WM ability in humans.

BACKGROUND. Although higher prevalence, disease activity, damage accumulation and mortality of systemic lupus erythematosus (SLE) are observed among Latin American, North American admixed population, African descendants and Native Americans, the information about SLE in Latin American countries, such as Mexico, is scarce. OBJECTIVES. To present Lupus RGMX, a multidisciplinary effort to generate a national digital patient registry to enrich the understanding of Mexican people with SLE. METHODS. Mexican patients with SLE registered between May 2021 and January 2023 in Lupus RGMX were included. Sociodemographic, socioeconomic and clinical characteristics, along with quality of life perception (QoL) were assessed using self-reported data. We compared the QoL obtained from patients with SLE with two groups of non-SLE Mexican subjects. Descriptive statistics, comparisons analyses and a multivariate nonparametric regression model were performed. RESULTS. A total of 1172 of lupus patients were included; of which 93.9% were women. The mean age±SD was 36.6±10.7 years, with 37.1% of the individuals between 41 and 50 years. The 24.9% reported a calculated monthly income of 430 USD (8,612 MXN). Lower QoL scores were observed in the SLE group, especially in subjects with lower socioeconomic level. Health perception, QoL perception and socioeconomic status were the variables with greater importance to predict total WHOQoL scores. CONCLUSION. The design and implementation of Lupus RGMX imply a pioneering approach to unraveling SLE in Mexicans. Further studies from Lupus RGMX will be focused on enriching the representation of the Mexican population and include other aspects that may allow us to improve our understanding of the disease in our population.