Arias B, Aguilera M, Moya J, Sáiz PA, Villa H, Ibáñez MI, García-Portillo MP, Bobes J, Ortet G, Fañanás L. The role of genetic variability in the SLC6A4, BDNF and GABRA6 genes in anxiety-related traits.
Objective: The aims of this study were to test the individual association of the serotonin transporter gene (SLC6A4), the brain-derived neurotrophic factor gene (BDNF) and the GABAAα6 receptor subunit gene (GABRA6) with anxiety-related traits and to explore putative gene–gene interactions in a Spanish healthy sample.
Method: A sample of 937 individuals from the general population completed the Temperament and Character Inventory questionnaire to explore Harm Avoidance (HA) dimension; a subsample of 553 individuals also filled in the Big Five Questionnaire to explore the Neuroticism dimension. The whole sample was genotyped for the 5-HTTLPR polymorphism (SLC6A4 gene), the Val66Met polymorphism (BDNF gene) and the T1521C polymorphism (GABRA6 gene).
Results: Homozygous individuals for the T allele of the T1512C polymorphism presented slightly higher scores for HA than C allele carriers (F = 2.96, P = 0.019). In addition, there was a significant gene–gene interaction on HA between the 5-HTTLPR and Val66Met polymorphisms (F = 3.4, P = 0.009).
Conclusion: GABRA6 emerges as a candidate gene involved in the variability of HA. The effect of a significant gene–gene interaction between the SLC6A4 and BDNF genes on HA could explain part of the genetic basis underlying anxiety-related traits.