1. ^*Molecular Cardiology, Institute of Medical Research, A Lanari, University of Buenos Aires, Buenos Aires, Argentina;
2. ^†CAIDEM, Chacabuco, Argentina;
3. ^‡Diabetes and Nutrition Section, Children's Hospital "Dr Ricardo Gutierrez";
4. ^§Department of Pharmacology, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina;
5. ^¶Molecular Genetics and Biology, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina.

Correspondence: Carlos J. Pirola Instituto de Investigaciones Médicas A. Lanari, Cardiología Molecular, Combatientes de Malvinas 3150, Buenos Aires 1427, Argentina. E-mail: pirola.carlos@lanari.fmed.uba.ar

^*The costs of publication of this article were defrayed, in part, by the payment of page charges. This article must, therefore, be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Received 3 June 2006; Revised  00; Accepted 5 September 2006.

Abstract

Obesity and hypertension are increasing medical problems in adolescents. Serotonin transporter (5-HTT) is involved in mood and eating disturbances. Encoded by the gene SLC6A4, the promoter shows functional insertion/deletion alleles: long (L) and short (S). Because individuals who are carriers for the short version are known to be at risk for higher levels of anxiety, we hypothesized that this variant may be associated with overweight. Data and blood samples were collected from 172 adolescents out of a cross-sectional, population-based study of 934 high school students. To replicate the findings, we also included 119 outpatients from the Nutrition and Diabetes Section of the Children's County Hospital. We found that the S allele was associated with overweight (BMI > 85th percentile), being a risk factor for overweight independently of sex, age, and hypertension [odds ratio (OR): 1.85; 95% confidence interval (CI): 1.13, 3.05; p < 0.02]. Additionally, in the outpatient study, compared with the homozygous LL subjects, S allele carriers showed a higher BMI z-score (1.47 1.09 vs. 0.51 1.4; p < 0.002) and were more frequent in overweight children. In conclusion, the S allele of the SLC6A4 promoter variant is associated with overweight being an independent genetic risk factor for obesity.