lassesen 11:53 pm on January 25, 2016  

DNA: Irritable Bowel Syndrome’s SNPs

“Irritable bowel syndrome (IBS) affects approximately 10.5% of the population (6.6% of men and 14.0% of women).[1]”

This is a continuation of what seem to have become a series of DNA Snps associated with CFS and conditions typically co-morbid.

  • GI symptom severity was associated with ADRA1D rs1556832 (P = 0.010). [2015] –
    • rs1042717,  rs174697
    • not in 23AndMe

However this articles does include a table that may be helpful for understand what association means:

table

If the percentage in the Healthy Controls and the IBS Patients for one particular item are far enough apart, and after doing some mathematics, the researchers will conclude that is a positive or negative association of the SNP with a patient or a symptom. For example rs174697 for G/G we have 65.6% versus 78.8% (thus having it suggests IBS is more likely), while for A/G we have 28.1% versus 18.7% suggesting IBS is less likely (1.5x less likely – sometimes called the Odds Ratio or “OR” i.e. 28.1/18.7).

A meta-analysis of immunogenetic Case-Control Association Studies in irritable bowel syndrome [2015].

  • [PMID 21636646OA-icon.png] Association of TNFSF15 polymorphism with irritable bowel syndrome “The Crohn’s disease risk allele rs4263839 G in the TNFSF15 gene was significantly associated with an increased risk of both IBS (p=2.2×10(-5); OR 1.37) and more pronouncedly, IBS-C (p=8.7×10(-7); OR 1.79) in the entire sample.”
  • [PMID 21304977OA-icon.png] An investigation of genome-wide studies reported susceptibility loci for ulcerative colitis shows limited replication in north Indians.
  • [PMID 25028192] Associations between TNFSF15 polymorphisms and susceptibility to ulcerative colitis and Crohn’s disease: A meta-analysis
  • [PMID 25824902] A meta-analysis of immunogenetic Case-Control Association Studies in irritable bowel syndrome

Link: https://www.23andme.com/you/explorer/snp/?snp_name=rs4263839 

  • The bad pair is “GG” (I have “AG”)

Genetic variants in CDC42 and NXPH1 as susceptibility factors for constipation and diarrhoea predominant irritable bowel syndrome [2014].

“Two SNPs associated independently in the exploratory and validation cohort: rs17837965-CDC42 with IBS-C (ORexploratory=1.59 (1.05 to 1.76); ORvalidation=1.76 (1.03 to 3.01)) and rs2349775-NXPH1 with IBS-D (ORexploratory=1.28 (1.06 to 1.56); ORvalidation=1.42 (1.08 to 1.88)).”

Only one SNP is available in 23AndMe, the one associated with diarrhoea.

Link: https://www.23andme.com/you/explorer/snp/?snp_name=rs2349775 (was previously associated with neuroticism )

  • From the literature that I could find,  “CC” is likely the bad one.