| MeSH | D003424 |
Crohn's disease is one type of inflammatory bowel disease; the Wikipedia article on Crohn's has quite a bit of information. Note that Crohn's disease is typically a recessive condition, requiring the inheritance of two nonfunctional alleles to develop fully. In genotypes reported in SNPedia, this is reflected correctly for homozygotes of causal variants (for example, rs2066844), but what is not easy to see are compound heterozygotes. For example, a person heterozygous for both rs2066844 and rs2066847 is correctly reported on a per genotype basis to be at ~3x higher risk for developing Crohn's at each of these two SNPs, but actually, this person is a compound heterozygote at much greater risk (>35x) for developing the disorder.
Causative SNPs for Crohn's disease, at least when found in homozygote/minor/recessive form or as compound heterozygotes, include:
A large study published in 2007 identified 17 SNPs each showing significant, though relatively small, association with increased risk for Crohn's disease. [PMID 17554300] These SNPs are:
- rs11805303
- rs10210302
- rs9858542 in the BSN gene
- rs17234657
- rs1000113
- rs10761659
- rs10883365
- rs17221417 in the NOD2 gene
- rs2542151
- rs12037606
- rs6596075 in the IBD5 gene
- rs6908425 in the CDKAL1 gene
- rs9469220
- rs7753394
- rs7807268
- rs6601764
- rs8111071
Other SNPs and genes have been associated with Crohn's disease:
- IL23R
- rs11209026 may minimize the risk of Crohn's disease
- Three other SNPs in the IL23R gene increase risk:
A 2015 study reported confirmation of 6 more loci in Koreans using a custom ImmunoChip: GPR35, ZNF365, ZMIZ1, NKX2-3, PTPN2, USP25. These achieved a 2% increase in explained variance(5.31 to 7.27%) . [PMID: 25489960]
