The association of the fat mass and obesity-associated gene (FTO) rs9939609 polymorphism and the severe obesity in a Brazilian population
Received 26 December 2018
Accepted for publication 28 February 2019
Published 23 May 2019 Volume 2019:12 Pages 667—684
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Ms Justinn Cochran
Peer reviewer comments 2
Editor who approved publication: Dr Konstantinos Tziomalos
Ana Carolina Proença da Fonseca,1 Gabriella Medeiros Abreu,1 Verônica Marques Zembrzuski,1 Mario Campos Junior,1 João Regis Ivar Carneiro,2 José Firmino Nogueira Neto,3 Giselda Maria Kalil Cabello,1 Pedro Hernán Cabello1,4
1Human Genetics Laboratory, Oswaldo Cruz Institute/FIOCRUZ, Rio de Janeiro, Brazil; 2Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; 3Department of Pathology and Laboratory, Rio de Janeiro State University, Rio de Janeiro, Brazil; 4Human Genetics Laboratory, Grande Rio University, Rio de Janeiro, Brazil
Background: Obesity occurs due to the interaction between the genetic background and environmental factors, including an increased food intake and a sedentary lifestyle. Nowadays, it is clear that there is a specific circuit, called leptin-melanocortin pathway, which stimulates and suppresses food intake and energy expenditure. Therefore, the aim of this study was to evaluate the influence of genetic variants related to appetite regulation and energy expenditure on severe obesity susceptibility and metabolic phenotypes in a Brazilian cohort.
Material and methods: A total of 490 participants were selected (298 severely obese subjects and 192 normal-weight individuals). Genomic DNA was extracted and polymorphisms in protein related to agouti (AGRP; rs5030980), ghrelin (GHRL; rs696217), neuropeptide Y (NPY; rs535870237), melanocortin 4 receptor (MC4R; rs17782313), brain-derived neurotrophic factor (BDNF; rs4074134) and fat mass and obesity-associated (FTO; rs9939609) genes were genotyped using TaqMan® probes. Demographic, anthropometric, biochemical and blood pressure parameters were obtained from the participants.
Results: Our results showed that FTO rs9939609 was associated with severe obesity susceptibility. This polymorphism was also related to body weight, body mass index (BMI), waist to weight ratio (WWR) and inverted BMI. Individuals carrying the mutant allele (A) showed higher levels of BMI as well as lower values of WWR and inverted BMI.
Conclusion: This study showed that FTO rs9939609 polymorphism plays a significant role in predisposing severe obesity in a Brazilian population.
Keywords: leptin-melanocortin pathway, FTO, obesity, polymorphisms, hypothalamus
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