No MYO9B variants or MYO9B haplotypes were found associated with CD, either before or after stratification of the patients for the human leucocyte antigen (HLA)-DQ2-positive risk factor.
To evaluate whether single nucleotide polymorphisms (SNPs) tagging the MYO9B susceptibility haplotype and the IBD5 locus (5q31-33) are involved in CD predisposition, we performed case-control and family-based analyses.
No MYO9B variants or MYO9B haplotypes were found associated with CD, either before or after stratification of the patients for the human leucocyte antigen (HLA)-DQ2-positive risk factor.
Besides the well known involvement of the HLA class II histocompatibility antigen (HLA)-DQ2.5 and -DQ8 heterodimers (encoded by particular combinations of the HLA-DQA1 and -DQB1 gene) in CD and the minor contribution of the CTLA-4 gene, recently the myosin IXB (MYO9B) gene has also been found to be genetically associated.
Based on this review, we performed genetic analysis of the MYO9B gene and the IL-2/IL-21 locus by genotyping SNPs that have been previously associated with coeliac disease or schizophrenia in 223 families, 108 unrelated individuals with schizophrenia and 120 controls.
However, for the first time, rs2305767MYO9B was revealed to have a strong association with TS (X<sup>2 </sup> = 58.6, p = .0001, and OR = 10.44 [95% C = 5.51-19.80]), supporting a high level of predisposition to CD among TS patients.
To address this, we performed an association study of a Norwegian IBD cohort (149 patients with Crohn's disease, 308 patients with ulcerative colitis and 562 healthy controls) using SNPs, which tagged the celiac disease associated MYO9B haplotype.
Polymorphisms in the 3' region of myosin IXB (Myo9B) are associated with chronic inflammatory gastrointestinal disorders like celiac disease and ulcerative colitis, assuming that variation in Myo9B influences the intestinal permeability.
Lack of reproducibility could be explained by no or negligible contribution of MYO9B to the genetic predisposition to CD in the Swedish/Norwegian population.
We have investigated how relevant regions contribute to CD susceptibility: CELIAC3 (CD28/CTLA4/ICOS region on 2q33) and CELIAC4 (19p13) as well as the tumour necrosis factor alpha (TNF-alpha) and the linfotoxin loci by case-control and association analyses.
Lack of reproducibility could be explained by no or negligible contribution of MYO9B to the genetic predisposition to CD in the Swedish/Norwegian population.
To date, seven studies have provided evidence for an association between the gene encoding for myosin IXB (MYO9B) and celiac disease (CD), and inflammatory bowel diseases, including single nucleotide polymorphisms (SNPs) rs2305767, rs1457092, and rs2305764.
Common variation in MYO9B was associated with susceptibility to inflammatory bowel disease in all 3 cohorts examined (most associated SNP, rs1545620; meta-analysis P = 1.9 x 10(-6); odds ratio, 1.2), with the same alleles showing association as reported for celiac disease.