MICB0106 gene polymorphism is associated with ulcerative colitis in central China

Background: The highly polymorphic nonclassical MHC class I chain-related genes A and B (MICA and MICB) encode stress-inducible glycoproteins expressed on various epithelial cells including intestinal epithelial cells. MICA and MICB gene polymorphisms and expressions are associated with autoimmune diseases but not known in ulcerative colitis (UC). Aims: To investigate the association of MICB exon 2-4 polymorphisms and soluble MICA (sMICA) expression with the susceptibility of UC in central China. Materials and methods: Genomic DNA was isolated from peripheral blood. The allele frequencies of MICB exon 2-4 were genotyped in 105 UC patients and 213 healthy controls by PCR single-stranded conformation polymorphism method. Thirty-two patients and 32 controls were selected for determining serum sMICA expression by ELISA. Results: Allele frequency of MICB0106 was significantly higher in UC patients than in healthy controls (19.0% vs. 8.9%, corrected P (Pc)=0.0006), especially in patients with extensive colitis (24.4% vs. 8.9%, Pc=0.0006), moderate and severe disease (24.1% vs. 8.9%, Pc=0.0006), extraintestinal manifestations (20.5% vs. 8.9%, Pc=0.012), male patients (22.1% vs. 8.0%, Pc=0.006), and patients over the age of 40 years (28.8% vs. 8.3%, Pc=0.0006). The sMICA level was significantly higher in UC than in healthy controls (604.41±480.43 pg/ml vs. 175.37±28.31 pg/ml, P=0.0001) but not associated with the MICB0106 genotypes. Conclusions: Overall, MICB0106 allele was positively associated with UC in the Han Chinese in central China. sMICA was highly expressed in UC but not associated with the MICB0106 genotype

Genome-wide association study of male sexual orientation

Family and twin studies suggest that genes play a role in male sexual orientation. We conducted a genome-wide association study (GWAS) of male sexual orientation on a primarily European ancestry sample of 1,077 homosexual men and 1,231 heterosexual men using Affymetrix single nucleotide polymorphism (SNP) arrays. We identified several SNPs with p < 10 -5 , including regions of multiple supporting SNPs on chromosomes 13 (minimum p = 7.5 × 10 -7 ) and 14 (p = 4.7 × 10 -7 ). The genes nearest to these peaks have functions plausibly relevant to the development of sexual orientation. On chromosome 13, SLITRK6 is a neurodevelopmental gene mostly expressed in the diencephalon, which contains a region previously reported as differing in size in men by sexual orientation. On chromosome 14, TSHR genetic variants in intron 1 could conceivably help explain past findings relating familial atypical thyroid function and male homosexuality. Furthermore, skewed X chromosome inactivation has been found in the thyroid condition, Graves' disease, as well as in mothers of homosexual men. On pericentromeric chromosome 8 within our previously reported linkage peak, we found support (p = 4.1 × 10 -3 ) for a SNP association previously reported (rs77013977, p = 7.1 × 10 -8 ), with the combined analysis yielding p = 6.7 × 10 -9 , i.e., a genome-wide significant association

Genetic Evidence Supporting the Association of Protease and Protease Inhibitor Genes with Inflammatory Bowel Disease: A Systematic Review

As part of the European research consortium IBDase, we addressed the role of proteases and protease inhibitors (P/PIs) in inflammatory bowel disease (IBD), characterized by chronic mucosal inflammation of the gastrointestinal tract, which affects 2.2 million people in Europe and 1.4 million people in North America. We systematically reviewed all published genetic studies on populations of European ancestry (67 studies on Crohn's disease [CD] and 37 studies on ulcerative colitis [UC]) to identify critical genomic regions associated with IBD. We developed a computer algorithm to map the 807 P/PI genes with exact genomic locations listed in the MEROPS database of peptidases onto these critical regions and to rank P/PI genes according to the accumulated evidence for their association with CD and UC. 82 P/PI genes (75 coding for proteases and 7 coding for protease inhibitors) were retained for CD based on the accumulated evidence. The cylindromatosis/turban tumor syndrome gene (CYLD) on chromosome 16 ranked highest, followed by acylaminoacyl-peptidase (APEH), dystroglycan (DAG1), macrophage-stimulating protein (MST1) and ubiquitin-specific peptidase 4 (USP4), all located on chromosome 3. For UC, 18 P/PI genes were retained (14 proteases and 4protease inhibitors), with a considerably lower amount of accumulated evidence. The ranking of P/PI genes as established in this systematic review is currently used to guide validation studies of candidate P/PI genes, and their functional characterization in interdisciplinary mechanistic studies in vitro and in vivo as part of IBDase. The approach used here overcomes some of the problems encountered when subjectively selecting genes for further evaluation and could be applied to any complex disease and gene family

Fine mapping of the IBD1 locus did not identify Crohn disease-associated NOD2 variants: implications for complex disease genetics.

Crohn disease (CD) is a chronic relapsing inflammatory condition of the gastrointestinal tract. Recently, polymorphisms in NOD2 (CARD15), a gene mapping to the chromosome 16 IBD1 susceptibility locus, have been associated with susceptibility to CD. One group identified the gene by using classic positional cloning methods. Here, we report linkage and fine mapping analyses using 27 microsatellite markers encompassing the IBD1 susceptibility locus in 131 CD affected sibling pairs, and a simplex family cohort. No evidence for linkage was observed, and microsatellite markers close to NOD2 did not show association. However, significant association was confirmed in 294 CD trios for the NOD2 variants Arg702Trp and Leu1007fsinsC. Our fine mapping study of the IBD1 locus did not enable us to identify NOD2 as a CD gene, despite the presence of association with disease-causing alleles. This study illustrates the difficulties facing microsatellite linkage and linkage disequilibrium mapping methods for identifying disease genes in complex traits

Pharmacogenomics and personalized medicine in clinical practice

The Santorini Conference on prospective biology, genomics and pharmacogenomics occurs every 2 years. On 30 September to 2nd October 2010, the fifth meeting in this series took place in Santorini, Greece. This conference has established a tradition of organizing a workshop each time to address the most recent developments and key issues in pharmacogenomics. This year, the workshop was chaired by Bryan Dechairo and Alain Huriez, and was titled 'Pharmacogenomics and personalized medicine in clinical practice'

Evidence From Autoimmune Thyroiditis Of Skewed X-Chromosome Inactivation In Female Predisposition To Autoimmunity

The etiologic factors in the development of autoimmune thyroid diseases (AITDs) are not fully understood. We investigated the role of skewed X-chromosome inactivation (XCI) mosaicism in female predisposition to AITDs. One hundred and ten female AITDs patients ( 81 Hashimoto's thyroiditis ( HT), 29 Graves' disease (GD)), and 160 female controls were analyzed for the androgen receptor locus by the HpaII/polymerase chain reaction assay to assess XCI patterns in DNA extracted from peripheral blood cells. In addition, thyroid biopsy, buccal mucosa, and hair follicle specimens were obtained from five patients whose blood revealed an extremely skewed pattern of XCI, and the analysis was repeated. Skewed XCI was observed in DNA from peripheral blood cells in 28 of 83 informative patients (34%) as compared with 10 of 124 informative controls (8%, P < 0.0001). Extreme skewing was present in 16 patients (19%), but only in three controls (2.4%, P < 0.0001). The buccal mucosa, and although less marked, the thyroid specimens also showed skewing. Analysis of two familial cases showed that only the affected individuals demonstrate skewed XCI patterns. Based on these results, skewed XCI mosaicism may play a significant role in the pathogenesis of AITDs.Wo

Multiple QTL influence the serum Lp(a) concentration: a genome-wide linkage screen in the PROCARDIS study.

The serum concentration of lipoprotein Lp (a) is known to be highly heritable and associated with cardiovascular risk. A genome-wide variance component linkage analysis was performed to localise quantitative trait loci (QTLs) influencing Lp(a) levels in a large cohort collected in the PROCARDIS coronary heart disease study. Highly significant linkage was detected at the previously described LP(a) locus on chromosome 6q27 (LOD 108). Taking into account the effect of the locus detected on chromosome 6, a highly significant LOD score was detected on chromosome 13q22-31 (LOD 7.0). Another significant region of linkage was observed on chromosomes 11p14-15 (LOD 3.5). The significant peak at 13q22-31 shows an essential overlap with a locus modulating cholesterol in familial hypercholesterolemia. If the gene underlying these loci is the same, it will be a promising candidate target for manipulating LDL-cholesterol and Lp(a). We also detected linkage at a previously identified locus influencing Lp(a) on chromosome 1q23 (LOD 1.5). Our findings provide new and confirmatory information about genomic regions involved in the quantitative variation of Lp(a) and serve as a basis for further studies of candidate genes in these regions