Introduction: Obesity is the result of a complex interaction between multiple genetic traits and psychological, behavioral, nutritional and environmental factors.
Objectives: The aims of the study were (a) to comparatively evaluate the presence of 20 candidate gene single nucleotide polymorphisms (SNPs) in morbidly obese patients, (2) their association to comorbid conditions and (3) their impact on weight loss after a Roux-en-Y gastric bypass (RYGB).
Patients and methods: Two hundred forty-nine patients were eligible for this study. Clinical, anthropometric, biochemical and demographic variables were analyzed. Body mass index (BMI) and composition were assessed by bioelectrical impedance. Twenty SNPs were included for analysis.
Results: There were 168 Mexican mestizos (67.5 %) and 81 (32.5 %) patients with other ancestral origin. One hundred fifty-nine (64.1 %) were females. Mean ± SD age of the general cohort was 41.1 ± 11.3 years (17-71). Preoperative mean ± SD BMI was 42.5 ± 6.5 kg/m2. There were no significant differences between mestizo and non-mestizo for most SNPs except for IFI, LIPC, and ST8SIA2. FTO (OR = 1.71; CI95 % = 1.14-2.57; p = 0.008) and APOB (OR = 0.31; CI95 % = 0.14-0.72; p = 0.004) result is statistically associated to high blood pressure and FTO (OR = 2.0; CI95 % = 1.3-3.1; p = 0.001), GNB3 (OR = 2.69; CI95 % = 1.0-7.2; p = 0.04), IFI30 (OR = 2.0; CI95 % = 1.16-3.6; p = 0.01), and MC4R (OR = 1.81; CI95 % = 1.13-2.9; p = 0.01) to type 2 diabetes (T2D). Based on ANOVA analysis, POMC (rs1042571) was the SNP most significantly associated to a higher weight loss after RYGB.
Conclusions: Obese patients have similar SNP frequencies. Several SNP results are statistically associated to high blood pressure and T2D. POMC was significantly associated to a higher surgically induced weight loss.
Keywords: Ancestral origin; Gastric bypass; Obesity surgery; Postoperative weight loss; SNP.