Summary To gain further insight into the genetic architecture of psoriasis, we conducted a meta-analysis of three genome-wide association studies (GWAS) and two independent datasets genotyped on the Immunochip, involving 10,588 cases and 22,806 controls in total. We identified 15 new disease susceptibility regions, increasing the number of psoriasis-associated loci to 36 for Caucasians. Conditional analyses identified five independent signals within previously known loci. The newly identified shared disease regions encompassed a number of genes whose products regulate T-cell function (e.g. RUNX3, TAGAP and STAT3). The new psoriasis-specific regions were notable for candidate genes whose products are involved in innate host defense, encoding proteins with roles in interferon-mediated antiviral responses (DDX58), macrophage activation (ZC3H12C), and NF-κB signaling (CARD14 and CARM1). These results portend a better understanding of shared and distinctive genetic determinants of immune-mediated inflammatory disorders and emphasize the importance of the skin in innate and acquired host defense.

NM A22834 (Albrecht) 3 Across a spectrum of living organisms, ranging from cyanobacteria to humans, it has been observed that biological functions follow a pattern of circadian rhythmicity.These endogenous rhythms display a periodicity close to 24 hours in the absence of environmental cues, thus reflecting the existence of an intrinsic biological clock. In mammals, circadian rhythms in different tissues are coordinated by a master clock located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus 1 . This circadian clock is thought to be advantageous in synchronising physiological and biochemical pathways, allowing the organism to anticipate daily changes, thus ensuring better adaptation to the environment 2 .The oscillatory mechanism of the circadian clock has been unraveled by means of genetic analysis in Drosophila and mammals [3][4][5] . In the latter, the heterodimeric complex of two transcriptional activators, CLOCK and BMAL1 (MOP3), induce the expression of several genes by interacting with the enhancer elements, termed E-boxes, of their promoters. Amongst these genes are Per1, Per2, Cry1 and Cry2, whose protein products, upon entering the nucleus, inhibit the activity of the CLOCK/BMAL1 complex, and thereby generating an inhibitory feedback loop driving recurrent rhythms in mRNA and protein levels of their own genes. This molecular mechanism seems to be present in the local clocks of most tissues and brain regions. Furthermore, these different clocks may then be synchronized by the SCN via neural and endocrine outputs 6 . Transporter 1, also known as Glast) is found to be reduced in these mice. Excess glutamate is cleared from the synaptic cleft by glutamate transporters 10 , located on astroglial cells and transported back to the neuron via the glutamine-glutamate cycle.A deficit in the removal of glutamate from the synaptic cleft, results in a hyperglutamatergic state and is suggested to produce alterations at the behavioral level 10,11 .Importantly, a hyper-glutamatergic state has been implicated in the aetiology of alcohol dependence [12][13][14] . We observe that in Per2 Brdm1 mutant mice voluntary alcohol consumption is enhanced. In humans we find an association between alcoholic patients and genetic variations in the human PER2 gene. Acamprosate, a medication thought to dampen a hyper-glutamatergic state in the alcohol dependent human brain 15-17 reduces augmented glutamate levels and normalizes enhanced alcohol consumption in Per2 Brdm1 mutant mice. These findings support the view that a hyperglutamatergic state can be involved in several aspects of alcohol dependence [12][13][14][18][19][20] . RESULTS Glutamate transporters in Per2 Brdm1 miceWild type and Per2 Brdm1 mutant mice differ in their behavioral response to a light pulse administered at zeitgeber time (ZT) 14 9 (ZT0 corresponds to lights on and ZT12 to lights off). Therefore, we set out to search for a difference in gene expression between wild type and Per2 Brdm1 mutant mice at ZT15. This time point has been chosen beca...

Psoriasis is a common inflammatory skin disease with a strong genetic component. We analyzed the genomic copy number polymorphism of the beta-defensin region on human chromosome 8 in 179 Dutch individuals with psoriasis and 272 controls and in 319 German individuals with psoriasis and 305 controls. Comparisons in both cohorts showed a significant association between higher genomic copy number for beta-defensin genes and risk of psoriasis.

To identify new susceptibility loci for psoriasis, we undertook a genome-wide association study of 594,224 SNPs in 2,622 individuals with psoriasis and 5,667 controls. We identified associations at eight previously unreported genomic loci. Seven loci harbored genes with recognized immune functions (IL28RA, REL, IFIH1, ERAP1, TRAF3IP2, NFKBIA and TYK2). These associations were replicated in 9,079 European samples (six loci with a combined P < 5 × 10⁻⁸ and two loci with a combined P < 5 × 10⁻⁷). We also report compelling evidence for an interaction between the HLA-C and ERAP1 loci (combined P = 6.95 × 10⁻⁶). ERAP1 plays an important role in MHC class I peptide processing. ERAP1 variants only influenced psoriasis susceptibility in individuals carrying the HLA-C risk allele. Our findings implicate pathways that integrate epidermal barrier dysfunction with innate and adaptive immune dysregulation in psoriasis pathogenesis

Psoriatic arthritis (PsA) is an inflammatory joint disease that is distinct from other chronic arthritides and which is frequently accompanied by psoriasis vulgaris (PsV) and seronegativity for rheumatoid factor. We conducted a genome-wide association study in 609 German individuals with PsA (cases) and 990 controls with replication in 6 European cohorts including a total of 5,488 individuals. We replicated PsA associations at HLA-C and IL12B and identified a new association at TRAF3IP2 (rs13190932, P = 8.56 × 10⁻¹⁷). TRAF3IP2 was also associated with PsV in a German cohort including 2,040 individuals (rs13190932, P = 1.95 × 10⁻³). Sequencing of the exons of TRAF3IP2 identified a coding variant (p.Asp10Asn, rs33980500) as the most significantly associated SNP (P = 1.13 × 10⁻²⁰, odds ratio = 1.95). Functional assays showed reduced binding of this TRAF3IP2 variant to TRAF6, suggesting altered modulation of immunoregulatory signals through altered TRAF interactions as a new and shared pathway for PsA and PsV