A single FTO gene variant rs9939609 is associated with weight change and insulin resistance improvement in response to a robotic sleeve gastrectomy in individuals with severe obesity.

Background: Genetic mechanisms have been involved in the weight response secondary to bariatric surgery.

Objective: The aim of our study was to evaluate the effects of the rs9939609 genetic variant on weight loss and metabolic parameters after sleeve gastrectomy.

Setting: Tertiary hospital.

Methods: A total of 95 participants were enrolled. Co-morbidities, biochemical evaluation, and anthropometric parameters were registered before and after 3-, 6-, and 12-month follow-up. Genotype of the rs9939609 fat mass and obesity-associated (FTO) gene was evaluated.

Results: We grouped the participants into 2 groups: carriers of A allele (TA+AA, 69.5%) and noncarriers of A allele (TT, 30.5%). We detected a statistically significant reduction of blood pressure, biochemical, and anthropometric parameters at 3 times during follow-up. After 6 months, changes of some parameters were greater in non-A allele carriers: weight (-39.6 + 4.0 kg versus -24.6 + 2.8 kg; P = .02), waist circumference (-21.1 + 2.1 cm versus -16.2 + 1.8 cm; P = .04), insulin (-12.3 + .9 mUI/L versus -8.9.1 + .2 mUI/L; P = .02), and homeostasis model assessment of insulin resistance (-3.1 + .1 units versus -2.3 + .1 units; P = .02 ). After 12 months, changes of the aforementioned parameters remained greater in non-A allele carriers. The percentage of participants with diabetes diminished earlier in the non-A allele carriers than A allele carriers at 6-month follow-up. The percentage of participants with diabetes at the end of the study was lower in non-A allele carriers (3.4% versus 12.1%; P = .02).

Conclusions: Our data suggest that non-A allele carriers of the genetic variant (rs9939609) of the FTO gene showed a better improvement of anthropometric and insulin levels in non-A allele carriers after a robotic sleeve gastrectomy. Both improvements are associated with a lower percentage of participants with diabetes at 12 months.