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

<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>

Association studies of G352A polymorphism of dopamine transporter gene in Han Chinese attention deficit hyperactivity disorder patients / 北京大学学报(医学版)

Objective:To investigate association of the new polymorphism G352A in the dopaminetransporter gene(DAT1)exon 15 with attention deficit hyperactivity disorder(ADHD)in Han Chinesechildren.Methods:The new mutant polymorphism G352A in the dopamine transporter gene(DAT1)ex-on 15 was found by the fluorescently-labeled dye-terminators assay.The study samples were comprised of337 ADHD children,207 unrelated controls and 201 integrated ADHD trios(included proband and bio-logical parents).Associations of polymorphisms with ADHD and its subtypes were examined by:(i)comparing cases and controls;and(ii)using family-based association study in transmission-disequilibri-um test(TDT).Results:The allele frequencies at the DAT1 G352A locus in the control samples were79.5% for 352G and 20.5% for 352A respectively.Association studies revealed no association betweenG352A in exon 15 of DAT1 and ADHD.But after a stratification by gender,there was possible associationbetween G352A and ADHD girls:the 352G allele had a tendency to be preferentially transmitted toADHD girls.Conclusion:There is no association between G352A,the new polymorphism,in exon 15 ofDAT1 and ADHD.The 352G allele has a tendency to be preferentially transmitted to ADHD girls,but thefindings require replication before drawing a definitive conclusion.