OBESITY RESEARCH Open Journal http://dx.doi.org/10.17140/OROJ-2-111 Obes Res Open J ISSN 2377-8385 Reward Defciency Syndrome in Children: Obesity and Metabolic Disorders are Associated with the SNP TaqIA C32806T of the DRD2 Gene Renata M. Pinto 1,2* , Daniela M. e Silva 1,2,3 , Fabrício J. Queiroz 1,2 , Fernanda R. Godoy 1,3 , Lilian S. Teodoro 1 , Isabella Lacerda 1,2 , Macks W. Gonçalves 1,3 , Irene P. Pinto 1,2 , Lysa Mi- nasi 1,4 , Thaís C. Vieira 1,4 and Aparecido D. da Cruz 1,2,4,5 1 Núcleo de Pesquisas Replicon, Departamento de Biologia, Pontifícia Universidade Católica de Goiás, Goiânia, Goiás, Brazil 2 Programa de Pós-Graduação Mestrado em Genética, Pontifícia Universidade Católica de Goiás, Goiânia, Goiás, Brazil 3 Programa de Pós-Graduação em Genética e Biologia Molecular, Laboratório de Genética e Biodiversidade, Universidade Federal de Goiás, Goiânia, GO, Brazil 4 Laboratório de Citogenética Humana e Genética Molecular, Secretaria do Estado da Saúde de Goiás (LACEN/SESGO), Goiânia, GO, Brazil 5 Programa de Pós-Graduação em Biotecnologia e Biodiversidade, Universidade de Brasília, Brasília, DF, Brazil * Corresponding author Renata M. Pinto, MD Núcleo de Pesquisas Replicon Departamento de Biologia Pontifícia Universidade Católica de Goiás, Goiânia, Goiás, Brazil E-mail: drarenatamachado@gmail.com Article History Received: July 27 th , 2015 Accepted: August 12 th , 2015 Published: August 13 th , 2015 Citation Pinto RM, e Silva DM, Queiroz FJ, et al. Reward defciency syndrome in children: obesity and metabolic dis- orders are associated with the SNP TaqIA C32806T of the DRD2 gene. Obes Res Open J. 2015; 2(2): 64-72. doi: 10.17140/OROJ-2-111 Copyright ©2015 Pinto RM. This is an open access article distributed under the Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Volume 2 : Issue 2 Article Ref. #: 1000OROJ2111 Research Page 64 ABSTRACT Background: Reward Defciency Syndrome (RDS) is a hypo-dopaminergic state that predis- poses to obsessive-compulsive behaviors. Obesity is part of RDS since the individual is pre- disposed to reward-driven eating behavior that leads to overeating. The allele A1 of the SNP C32806T in Dopamine D2 receptor gene (DRD2) is associated with reduction of DRD2 levels and higher BMI in adults. DRD2 are expressed in beta cells and modulate insulin secretion. The aim of this study is to investigate the relation between this SNP and obesity and metabolic alterations in children. Methods: Fifty fve obese children and 50 healthy controls were analyzed for DRD2 Taq1A polymorphism Genotyping was performed by polymerase chain reaction and restriction frag- ment length polymorphism. Glucose, insulin and lipid profle were measured. The Homeostatic model assessment (HOMA) was calculated. Results: We found three genotypes: A1A1(12,4%), A1A2(33,3%) and A2A2(54,3%). The A1 allele was more present in: obese than in euthrophic (34,5%*23%), in children with altered HOMA ß (38,2% * 24,6%), children with altered Total Cholesterol (35,2%*19,5%) and lower levels of triglycerides. Children were divided in 4 subgroups in accordance to the function of pancreatic beta cells and BMI-Z; subgroups with normal secreting pancreatic beta cell dem- onstrated signifcant difference for allelic and genotypic distribution, with lower presence of A1A1 and A1A2 genotypes and higher presence of A2 allele. Conclusions: Besides confrming the association with childhood obesity, our results show for the frst time that: A1 allele is associated with TC≥170 mg/dl, lower TG levels and HOMA ß ≥175. A2 allele is associated with normal HOMA ß, being a protective factor for pancreatic secretion. The recognition of predisposed individuals through determinations of risks polymor- phisms can lead to new paths for treatment and prevention of metabolic abnormalities. KEYWORDS: Childhood obesity; DRD2 gene; HOMA; Dopamine; Genetic polymorphism. ABBREVIATIONS: RDS: Reward Defciency Syndrome; DRD2: Dopamine D2 receptor gene; WHO: World Health Organization; PET: Positron Emission Tomography; HOMA: Homeosta-