102 Brief report Arginine vasopressin receptor gene-based single-nucleotide polymorphism analysis in attention deficit hyperactivity disorder Dirk van Westa,c,d,e, Jurgen Del-Faveroa,c, Dirk Deboutted,e, Christine Van Broeckhovenb,c and Stephan Claesa,c,f Psychiatric Genetics 2009, 19:102–103 a Department of Molecular Genetics, Applied Molecular Genomics Group, Department of Molecular Genetics, Neurodegenerative Brain Diseases Group, VIB, cUniversity of Antwerp (UA), dUniversity Center of Child and Adolescent Psychiatry Antwerp (UKJA), eCollaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp and fUniversity Psychiatric Center, Campus Leuven, University of Leuven, Leuven, Belgium b Introduction Several studies in clinical and developmental neuroscience have suggested that hypothalamic–pituitary–adrenal-axis dysfunctions are likely to be important in patients with attention deficit hyperactivity disorder (ADHD) (Kariyawasam et al., 2002; Hong et al., 2003; Yang et al., 2007). Recently, our research group developed an AVPR1b single-nucleotide polymorphism (SNP) map and studied them in a haplotype-based association approach in a sample of patients with affective disorders (van West et al., 2004). To investigate whether these AVPR1b SNPs are also involved in the liability to develop ADHD, we performed an association analysis with these SNPs in a patient/control sample. Methods The patient sample consisted of 57 unrelated ADHD patients. The sex ratio was 47 males : 10 females, and the mean age at inclusion was 8.61 ± 1.91 years. The control sample consisted of 106 unrelated healthy children. The sex ratio was 49 males : 57 females, and the mean age at inclusion was 8.74 ± 1.63 years. All patients and control individuals had grandparents of Belgian nationality. The SNPs rs28536160, rs28373064, rs33976516, rs33985287 and rs33933482 were genotyped using pyrosequencing (Pyrosequencing AB, Uppsala, Sweden). The GENEPOP Version 3.4 program (http://genepop.curtin.edu.au/) was used to compare overall allele and genotype distributions for each SNP in ADHD patients and controls, and to test the Hardy–Weinberg equilibrium. To estimate SNP haplotype frequencies in ADHD patients and controls, the expectation maximization algorithm provided by the Arlequin package was applied (http://lgb.unige.ch/arlequin/). Correspondence to Dr Dirk van West, MD, MSc, University Center of Child and Adolescent Psychiatry (UKJA), ZNA Middelheim, University of Antwerp, Lindendreef 1, Antwerp B-2020, Belgium Tel: + 32 3 280 49 00; fax: + 32 3 280 49 14; e-mail: dirk.vanwest@zna.be Received 18 October 2008 Revised 24 November 2008 Accepted 24 November 2008 observed for rs28373064 (P = 0.010), with the minor allele C more frequently present in ADHD patients. In the genotype distributions this is reflected by a significant increase of CT heterozygotes of rs28373064 in the ADHD patients (P = 0.020). The overall distribution of the five AVPR1b haplotypes was significantly different between patients and controls (P = 0.006). The haplotype with major alleles A-T-C-A-G, respectively for five SNPs of rs28536160_rs28373064_rs33976516_rs33985287_rs33933482, had an estimated frequency of 78% in ADHD patients and 86% in controls. Carrying this major haplotype decreased the probability of developing ADHD in this population (odds ratio = 0.62, 95% confidence interval = 0.27–1.43). Moreover, the haplotype with major alleles A-C-G-G-A, respectively for five AVPR1b SNPs, had an estimated frequency of 7% in ADHD patients and only 1% in controls. Carrying this haplotype increased the probability of developing ADHD in this population (odds ratio = 7.92, 95% confidence interval = 0.86–72.68). Discussion The results of this study imply that a genetic variation in the promoter region or the 50 end of the AVPR1b gene plays a role in the vulnerability for ADHD in the general population. In a recent article by Dempster et al. (2007), an AVPR1b family-based association study was performed in 464 children with a mood disorder. They also found a trend for transmission to the affected offspring for rs28373064. Because no corrections were made for multiple testing, these results should be interpreted cautiously. The association should also be replicated in additional and larger patient–control samples. Results Acknowledgements All SNPs were in Hardy–Weinberg equilibrium. In the patient–control sample a significant difference in allele distribution between ADHD patients and controls was Fundings: This work has been supported by the Special Research Fund of the University of Antwerp (UA), the Fund for Scientific Research Flanders (FWO-F), 0955-8829 c 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI: 10.1097/YPG.0b013e32832a0b2b Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Gene-based SNP analysis in ADHD van West et al. 103 The National Fund for Scientific Research (FNRS) and the Interuniversity Attraction Poles (IUAP) program P5/19 of the Belgian Science Policy Office. References Dempster EL, Burcescu I, Wigg K, Kiss E, Baji I, Gadoros J, et al. (2007). Evidence of an association between the vasopressin V1b receptor gene (AVPR1b) and childhood-onset mood disorders. Arch Gen Psychiatry 64: 1189–1195. Hong HJ, Shin WS, Lee EH, Oh YH, Noh KS (2003). Hypothalamic-Pituitary-Adrenal Reactivity in boys with attention deficit hyperactivity disorder. Yonsei Med J 4:608–614. Kariyawasam SH, Zap F, Handley SL (2002). Reduced salivary cortisol in children with comorbid attention deficit hyperactivity disorder and oppositional defiant disorder. Neuroendocrinol Lett 23:45–48. Van West D, Del-Favero J, Aulchenko Y, Oswald P, Souery D, Forsgren T, et al. (2004). A major SNP haplotype of the arginine vasopressin 1B receptor protects against recurrent major depression. Mol Psychiatry 9:287–292. Yang SJ, Shin DW, Noh KS, Stein MA (2007). Cortisol is inversely correlated with aggression for those boys with attention deficit hyperactivity disorder who retain their activity to stress. Psychiatry Res 153:55–60. Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.