Association of polymorphisms in 5-HTT (SLC6A4) and MAOA genes with measures of obesity in young adults of Portuguese origin

Arch Physiol Biochem. 2016;122(1):8-13. doi: 10.3109/13813455.2015.1111390. Epub 2015 Dec 23.


Objectives: To investigate the association of polymorphisms in SLC6A4 and MAOA genes with overweight (including obesity).

Material and methods: Young adults (n = 535) of Portuguese origin were genotyped for the SLC6A4 polymorphisms 5-HTTLPR and STin2 and a MAOA VNTR. BMI and body fat percentage were measured and a questionnaire was used to assess individual's sport practicing habits.

Results: In whole study sample, haplotype-based analysis revealed significant association with overweight/obesity for the individual 5-HTTLPR/Stin2 haplotype L10 (p = 0.04). In men, the MAOA 3R genotype was nominally associated with body fat (p = 0.04). In inactive individuals, overweight/obesity was found significantly associated with 5-HTTLPR L-allele (p = 0.01) and nominally associated with STin2 10-allele (p = 0.03). A significant association was also found testing for all haplotype effects (χ(2 )= 8.7; p = 0.03).

Conclusions: We found some evidences for the association of SLC6A4 and MAOA genes with measures of obesity. Our results suggest physical inactivity accentuates the influence of SLC6A4 polymorphisms on obesity risk.

Keywords: 5-HTTLPR and STin2 polymorphisms; MAOA VNTR polymorphism; Portugal; overweight and obesity; serotonin transporter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Case-Control Studies
  • Cross-Sectional Studies
  • Female
  • Genotyping Techniques
  • Humans
  • Male
  • Minisatellite Repeats / genetics
  • Monoamine Oxidase / genetics*
  • Obesity / enzymology
  • Obesity / genetics*
  • Polymorphism, Single Nucleotide*
  • Portugal
  • Serotonin Plasma Membrane Transport Proteins / genetics*
  • Young Adult


  • SLC6A4 protein, human
  • Serotonin Plasma Membrane Transport Proteins
  • Monoamine Oxidase
  • monoamine oxidase A, human