2 AbstractPurpose: To evaluate the role of cytochrome 450 2D6 (CYP2D6) and ABCB1 variants on plasma risperidone concentrations and treatment response in 83 drug naive patients with first episode of psychosis.Methods: All patients were treated with risperidone for 8 weeks. The CYP2D6 genotyping was performed by allele-specific PCR-RFLP (for *3,*4,*6) and long PCR (for duplications and *5), while real-time PCR method was used for ABCB1 G2677T/A and C3435T. Plasma concentrations of risperidone and 9-OH risperidone were measured by high-preformance liquid chromatography.Results: The number of patients with the CYP2D6 wild type (wt/wt), wt/mutation (mut) and mut/mut genotype was 43, 32 and 8, respectively. The number of patients with the ABCB1 2677G/G , G/T, T/T variants was 29, 42 and 12, respectively; those with the 3435C/C, C/T and T/T was 25, 37 and 21, respectively. The CYP2D6 genotype has strong effect on steady-state dose-corrected plasma levels of risperidone, its 9-OH metabolite and active moiety, while ABCB1 2677T/T and 3435T/T genotypes hold similarly strong effects on active moiety C/D. The CYP2D6 poor metabolizers had significantly higher levels of risperidone C/D and active moiety C/D, and lower levels of 9-OH risperidone C/D. The ABCB1 3435T allele and the ABCB1 2667T-3435T haplotype carriers were more frequent among subjects without extrapyramidal syndrome. Patients showed significant improvements in positive and general symptoms, but not in negative symptoms. These changes were not related to variations in genetic and drug concentration data.Conclusion: Our findings suggest that CYP2D6 and ABCB1 G2677T and C3435T might be useful determinants of risperidone plasma concentrations, but the clinical implications of these associations in relation to treatment response and side-effects remains unclear.

Post-traumatic stress disorder (PTSD) is a common and debilitating disorder. The risk of PTSD following trauma is heritable, but robust common variants have yet to be identified by genome-wide association studies (GWAS). We have collected a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls. We first demonstrate significant genetic correlations across 60 PTSD cohorts to evaluate the comparability of these phenotypically heterogeneous studies. In this largest GWAS meta-analysis of PTSD to date we identify a total of 6 genome-wide significant loci, 4 in European and 2 in African-ancestry analyses. Follow-up analyses incorporated local ancestry and sex-specific effects, and functional studies. Along with other novel genes, a non-coding RNA (ncRNA) and a Parkinson's Disease gene, PARK2, were associated with PTSD. Consistent with previous reports, SNP-based heritability estimates for PTSD range between 10-20%. Despite a significant shared liability between PTSD and major depressive disorder, we show evidence that some of our loci may be specific to PTSD. These results demonstrate the role of genetic variation contributing to the biology of differential risk for PTSD and the necessity of expanding GWAS beyond European ancestry.Comparability of PGC2 studies PGC2 compiled the largest collection of global PTSD GWAS to date, with subjects recruited from both clinically deeply characterized, small patient groups and large cohorts with self-reported PTSD symptoms. We did not restrict the type of trauma subjects were exposed to, and trauma included both civilian and/or military events, often with pre-existing exposure to childhood trauma. To evaluate the comparability of these phenotypically heterogeneous studies we first estimated genetic correlations with LDSC, 15 a method that leverages GWAS summary results, the only data type available to PGC-PTSD for several of the larger military and non-US cohorts. We found significant genetic correlations (r g ) between studies using a cross-validation approach including all PGC2 EUA subjects (10 runs with studies randomly placed into 2 groups; mean r g = 0.56, mean SE = 0.23, mean p = 0.029, Supplementary Table 8).Next, additional analyses on the UK Biobank cohort (UKBB) were performed. This cohort comprises a very large proportion of the data, with almost as many EUA cases as the rest of the EUA PGC2 combined (referred to as PGC1.5). PTSD screening in UKBB was based on self-reported symptoms from a mental health survey. 16 We found a considerable genetic correlation between the UKBB and PGC1.5 EUA subjects (r g = 0.73, SE = 0.21, p = 0.0005; Supplementary Table 9). Further, sensitivity analyses in the UKBB using 3 alternative inclusion criteria for PTSD cases and controls showed stable correlations with PGC1.5 (P1 -P3; r g = 0.72 -0.79; Supplementary Table 10). Subsequent analyses were based on the UKBB phenotype including the largest number of subjects (P1; N = 126,188). Sex-stratified genetic correlations support the findings of a significant genetic signal...

The gamma-aminobutyric acid (GABA) neurotransmitter system has been implicated in the pathogenesis of mood disorders. To test this hypothesis we carried out an association study between a dinucleotide repeat polymorphism in the GABA_A receptor α5 subunit gene and bipolar and unipolar mood disorders. Our results suggest a possible involvement of this gene in unipolar but not in bipolar disorder.