Association study of serotonin 2A receptor (5-HT2A) and serotonin transporter (5-HTT) gene polymorphisms with schizophrenia

Objective: To investigate (i) the association between four serotonergic polymorphisms (A-1438G and T102C of the 5-HT2A receptor gene, and 5-HTTLPR of the 5-HT transporter gene) and schizophrenia and (ii) the potential interaction of those polymorphisms in the development of schizophrenia. Subjects and methods: 227 outpatients with schizophrenia (DSM-IV criteria) and 420 unrelated healthy controls from Asturias (Northern Spain) were genotyped using standard methods. Results: Both groups showed Hardy-Weinberg equilibrium for the analyzed genetic variability. A-1438G and T102C polymorphisms are in complete linkage disequilibrium in our population. There was an apparent difference in the distribution of genotypes for the A-1438G (or T102C) polymorphisms (p=0.018, not significant after a Bonferroni correction). The 5-HT2A - 1438A (or 102T) allele was significantly more frequent in patients than controls (0.53 and 0.45, respectively; corrected p=0.028, OR= 1.39 (95% Cl= 1. 11-1.75)). Genotype and allele distributions for 5-HTT polymorphisms were similar in both groups. However, assessment of the combined influence of 5-HT2A A-1438G and 5-HTTLPR polymorphisms demonstrated a significant effect (X-2 (3)= 11.51, p=0.009), whereby the combination of - 1438A and 5-HTTLPR S alleles was associated with schizophrenia. Conclusions: Our findings support a possible synergistic effect of genetic factors influencing serolonergic neurotransmission on susceptibility to schizophrenia. (c) 2007 Elsevier Inc. All rights reserved.