Pharmacogenetics and pharmacogenomics in psoriasis treatment: current challenges and future prospects.

INTRODUCTION: Topical, systemic, oral disease modifying, and biologic agents are part of the armamentarium to manage psoriatic disease. The choice of therapy depends upon disease severity, relevant co-morbidities and patient preference. There is great variability in patient response with these agents, and there is still no clear method of selecting the preferred therapeutic agent for efficacy or lack of adverse events. AREAS COVERED: This article will review the pharmacogenetic and pharmacogenomic targets that are currently known with respect to psoriasis vulgaris, and the most frequent co-morbidity of psoriasis, psoriatic arthritis. EXPERT OPINION: Presently, no clinically actionable biomarker exists for any therapeutic agent used to treat psoriasis or psoriatic arthritis. The lack of validated outcome measures and conflicting results of open-label studies conducted may be attributed to a multitude of issues that confound discovery. Consequently, studies have been underpowered to identify genes or genetic variants worth translating to clinical practice. In order to achieve a pharmacogenetic/pharmacogenomic signature, improvements in study design of future investigations are required, including carefully designed prospective studies. It is imperative to combine known clinical, serological, and molecular markers with consistent outcomes and an adequate health economic evaluation before they can be adopted widely in clinical practice.

Polymorphisms in the selenoprotein S and 15-kDa selenoprotein genes are associated with altered susceptibility to colorectal cancer.

Selenium (Se), a dietary trace metal essential for human health, is incorporated into ~25 selenoproteins including selenoprotein S (SelS) and the 15-kDa selenoprotein (Sep15) both of which have functions in the endoplasmic reticulum protein unfolding response. The aim of this study was to investigate whether genetic variants in such selenoprotein genes are associated with altered risk of colorectal cancer (CRC). A Korean population of 827 patients with CRC and 733 healthy controls was genotyped for 7 SNPs in selenoprotein genes and one SNP in the gene encoding manganese superoxide dismutase using Sequenom technology. Multivariate logistic regression analysis showed that after adjustment for lifestyle factors three SNP variants were associated with altered disease risk. There was a mean odds ratio of 2.25 [95% CI 1.13,4.48] in females homozygous TT for rs34713741 in SELS with the T variant being associated with higher risk of rectal cancer, and odds ratios of 2.47 and 2.51, respectively, for rs5845 and rs5859 in SEP15 with the minor A and T alleles being associated with increased risk of male rectal cancer. The data indicate that the minor alleles for rs5845, rs5859 and rs34713741 are associated with increased rectal cancer risk and that the effects of the three SNPs are dependent on gender. The results highlight potential links between Se, the function of two selenoproteins involved in the protein unfolding response and CRC risk. Further studies are required to investigate whether the effects of the variants on CRC risk are also modulated by dietary Se intake.

Genomic polymorphism at the interferon-induced helicase (IFIH1) locus contributes to Graves' disease susceptibility.

CONTEXT: A recent large-scale analysis of nonsynonymous coding polymorphisms showed strong evidence that an alanine to threonine amino acid change at codon 946 of the interferon-induced helicase (IFIH1) gene (SNP ID rs1990760) was associated with type 1 diabetes. Previous investigations have also demonstrated that an intronic polymorphism (termed PD1.3; SNP ID rs11568821) in the programmed cell death (PDCD1) gene was associated with systemic lupus erythematosus and rheumatoid arthritis. OBJECTIVE: We sought to replicate these genetic associations in Graves' disease and autoimmune Addison's disease patient cohorts. PATIENTS AND METHODS: A total of 602 Graves' disease subjects, 214 Addison's disease subjects, and 446 healthy controls were genotyped for the IFIH1 and PDCD1 single-nucleotide polymorphisms using mass spectrometer analysis of primer extension products (Sequenom). RESULTS: The alanine-carrying allele at the IFIH1 codon 946 polymorphism was present in 796 of 1204 (66%) Graves' disease patient alleles compared with 508 of 892 (57%) control subject alleles [odds ratio 1.47 (5-95% confidence interval, 1.23-1.76); P = 1.9 x 10(-5)]. In contrast, there was no association of alleles at this marker in autoimmune Addison's disease. Neither was there evidence for association in either patient cohort at the PD1.3 polymorphism. CONCLUSIONS: We confirm a significant contribution of the Ala946Thr IFIH1 polymorphism to organ-specific autoimmune diseases, extending the range of conditions associated with this variant to include Graves' disease. This polymorphism may also contribute to several other autoimmune disorders.