No evidence for an association between the T102C and 1438 G/A polymorphisms of the serotonin 2A receptor gene in attention deficit/hyperactivity disorder in a Turkish population

Disturbances in the serotonergic neurotransmission system have been implicated in the etiology of attention deficit/hyperactivity disorder (ADHD). As the importance of genetic factors is well established, genes encoding for proteins of the serotonergic pathway are important candidates to unravel the underlying genetic contribution. We previously demonstrated that the polymorphisms of the serotonin transporter gene promoter and regions of variable number of tandem repeats were involved in the pathogenesis of ADHD. The purpose of this study was to examine the relationship between ADHD and two polymorphisms (T102C and 1438 G/A) in the 5-HT2A gene in a sample of Turkish children. Using the PCR technique, these polymorphisms were assessed in 70 patients with ADHD and in 100 healthy controls. There was no significant difference between the frequencies of the T, C, G and A alleles of both groups. No association was found between the studied polymorphisms of the 5-HT2A gene and ADHD in this sample consisting of Turkish children. Overall, our results suggest that the investigated 5-HT2A polymorphisms are not major susceptibility factors in the etiology of ADHD.