Original Article
Molecular Psychiatry advance online publication 20 October 2009; doi: 10.1038/mp.2009.92
C Dong1, M-L Wong2 and J Licinio2
- Department of Psychiatry and Behavioral Sciences, Center for Pharmacogenomics, University of Miami Miller School of Medicine, Miami, FL, USA
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
Correspondence: Professor J Licinio, John Curtin School of Medical Research, The Australian National University, GPO Box 334, Canberra, ACT 2601, Australia. E-mail: julio.licinio@anu.edu.au
Received 20 July 2009; Accepted 28 July 2009; Published online 20 October 2009.
We studied seven genes that reflect events relevant to antidepressant action at four sequential levels: (1) entry into the brain, (2) binding to monoaminergic transporters, and (3) distal effects at the transcription level, resulting in (4) changes in neurotrophin and neuropeptide receptors. Those genes are ATP-binding cassette subfamily B member 1 (ABCB1), the noradrenaline, dopamine, and serotonin transporters (SLC6A2, SLC6A3 and SLC6A4), cyclic AMP-responsive element binding protein 1 (CREB1), corticotropin-releasing hormone receptor 1 (CRHR1) and neurotrophic tyrosine kinase type 2 receptor (NTRK2). Sequence variability for those genes was obtained in exonic and flanking regions. A total of 56 280 000 bp across were sequenced in 536 unrelated Mexican Americans from Los Angeles (264 controls and 272 major depressive disorder (MDD)). We detected in those individuals 419 single nucleotide polymorphisms (SNPs); the nucleotide diversity was 0.00054
0.0001. Of those, a total of 204 novel SNPs were identified, corresponding to 49% of all previously reported SNPs in those genes: 72 were in untranslated regions, 19 were in coding sequences of which 7 were non-synonymous, 86 were intronic and 27 were in upstream/downstream regions. Several SNPs or haplotypes in ABCB1, SLC6A2, SLC6A3, SLC6A4, CREB1 and NTRK2 were associated with MDD, and in ABCB1, SLC6A2 and NTRK2 with antidepressant response. After controlling for age, gender and baseline 21-item Hamilton Depression Rating Scale (HAM-D21) score, as well as correcting for multiple testing, the relative reduction of HAM-D21 score remained significantly associated with two NTRK2-coding SNPs (rs2289657 and rs56142442) and the haplotype CAG at rs2289658 (splice site), rs2289657 and rs2289656. Further studies in larger independent samples will be needed to confirm these associations. Our data indicate that extensive assessment of sequence variability may contribute to increase understanding of disease susceptibility and drug response. Moreover, these results highlight the importance of direct re-sequencing of key candidate genes in ethnic minority groups in order to discover novel genetic variants that cannot be simply inferred from existing databases.




exposure mechanisms requires precise measurement of exposure and outcomes. We tested whether a functional polymorphism in the gene encoding the enzyme monoamine oxidase A (MAOA) interacts with exposure to predict pathways to adolescent antisocial behavior. We assessed both clinical and information-processing outcomes. One hundred seventy-six adolescents and their mothers participated in a follow-up of a pregnancy cohort with well-characterized exposure. A sex-specific pattern of gene
60 years were enrolled. Standard clinical evaluations were performed on all participants and blood samples obtained for genotyping. 1.5-T MRI (magnetic resonance imaging) data were obtained at baseline and approximately 2 years later. These scans were processed using a semi-automated segmentation process, which allowed for the calculation of WML volume at each time point. Statistical models were tested for the relationship between change in WML volume and genotype, while also controlling for age, sex, diagnostic strata, baseline WML volume and comorbid cerebrovascular risk factors. In men, AGTR1 1166A allele homozygotes exhibited significantly less change in WML volume than 1166C carriers. We also found that men reporting hypertension (HTN) with the AGTR2 3123C allele exhibit less change in WML volume than hypertensive men with the 3123A allele, or men without HTN. There were no significant relationships between these polymorphisms and change in WML volume in women. No significant gene–gene or gene–depression interactions were observed. Our results parallel earlier observed gender differences of the relationship between other renin–angiotensin system polymorphisms and HTN. Further work is needed to determine whether these observed relationships are secondary to polymorphisms affecting response to antihypertensive medication, and whether antihypertensive medications can slow WML progression and lower the risk of morbidity associated with WMLs.
