Association between serotonin 2C gene polymorphisms and attention deficit hyperactivity disorder in children with or without comorbidity of disruptive behavior disorder / 中华儿科杂志

ABSTRACT

<p><b>OBJECTIVE</b>Disruptive behavior disorder (DBD) is one of the main comorbidity of attention deficit hyperactivity disorder (ADHD). Previous studies showed significantly different serotonin function between ADHD children with and without the comorbidity of DBD. Therefore, it is needed to compare these two groups in terms of serotonin receptor gene polymorphisms, which may provide further evidence for the previous studies. The current study aimed to investigate the relationship between two serotonin receptor 2C (HTR2C) gene polymorphisms, that are C-759T and G-697C polymorphisms, and ADHD with or without concomitant DBD.</p><p><b>METHOD</b>Blood samples were taken from 237 trios with probands of ADHD with DBD comorbidity and 251 trios with probands of ADHD without comorbidity of DBD. All the subjects were from the ADHD clinic of Peking University Sixth Hospital. DNA was extracted and PCR was performed to amplify the fragments containing both C-759T and G-697C polymorphisms. AciI was used to detect different alleles of the two polymorphisms. Both allele-based and haplotype-based TDT analyses were used to test the association of the two polymorphisms of HTR2C gene and ADHD with or without comorbidity of DBD.</p><p><b>RESULTS</b>The haplotypes -759C (chi(2) = 4.25, P = 0.04), -697G(chi(2) = 3.21, P = 0.07), as well as -759C/-697G were over-transmitted (chi(2) = 4.31, P = 0.04) to the probands of ADHD without DBD. No biased transmission of any allele and haplotype were found in families with probands of ADHD with DBD.</p><p><b>CONCLUSION</b>ADHD with or without the comorbidity DBD was different at the level of HTR2C gene polymorphisms of C-759T and G-697C. HTR2C is related to ADHD without DBD, while not related to ADHD with DBD. The results suggested that the two groups may have different genetic background, at least in HTR2C.</p>