Table of Contents
International Journal of Medical Genetics
Volume 2015, Article ID 123159, 6 pages
http://dx.doi.org/10.1155/2015/123159
Research Article

The Association of 5-HTTLPR XLL Genotype with Higher Cortisol Levels in African Americans

1Human Performance Laboratory, Uniformed Service University of the Health Sciences, Bethesda, MD 20814, USA
2Naval Medical Research Center, Silver Spring, MD 20910, USA
3Children’s National Medical Center, Washington Hospital Center, Washington, DC 20010, USA

Received 29 August 2014; Revised 15 December 2014; Accepted 18 December 2014

Academic Editor: Kei Kamide

Copyright © 2015 Carmen L. Contreras-Sesvold et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Genetic variants of the human serotonin transporter (SERT) may contribute to HPA axis dysregulation. SERT has two promoter region polymorphisms (5-HTTLPR: VNTR and SNP: rs25531), which may alter levels of SERT protein and its function. Combining these polymorphisms creates a functional polymorphism (FN) which may modulate mRNA expression. This study examines the relationship between these genetic variants and morning and evening salivary samples of both cortisol and dehydroepiandrosterone sulfate (DHEAS) concentrations in 269 African American (AA) adults. Resultant allele frequencies for the VNTR, SNP, and FN genotypes were 70% L (2% XLL), 84% A, and 54% LA (2% XLLA), respectively. The XLL genotype was associated with significantly higher concentrations of cortisol (~3X) and DHEAS (~2X) for both VNTR and FN polymorphisms. No significant differences were found for SNP genotypes. Conclusions were that persons with VNTR and FN XLL polymorphisms had significantly higher cortisol and DHEAS concentrations than other genotypes. AAs also appear to have a higher frequency of the rare XL allele than Caucasians. Whether the XLL genotype predisposes AAs to greater health challenges will require further research to determine the implications of these findings.