In a genome-wide association study, investigators linked irritable bowel syndrome to certain DNA variants found only in women, which researchers said could explain why the condition is less common in men.
“Although we cannot point to individual genes at this early stage, we believe these results are exciting, as they converge with existing data on female preponderance and a role of sex-hormones in IBS,” Mauro D’Amato, PhD, visiting professor in the department of medicine at Karolinska Institutet, said in a press release.
Because genetic factors associated with IBS are suspected but poorly studied, D’Amato and colleagues evaluated genetic and health data from 500,000 participants in the U.K. Biobank cohort. They studied more than 7 million single-nucleotide polymorphisms (SNPs) in 9,576 patients with a self-reported diagnosis of IBS compared with 336,499 controls. Then they further evaluated significant findings from this cohort in 2,045 patients with IBS and 7,955 controls from Europe and the U.S., and in 249 individuals from a population sample in Sweden.
“Exploiting the large U.K. Biobank resource, as well as several patient cohorts from European and U.S. expert centers, we have been able to study genetic predisposition to IBS with increased statistical power, better than ever before,” D’Amato said in the press release.
In the U.K. Biobank cohort, they found an increased risk for IBS was significantly associated with genetic variants on chromosome 9 in women (chromosome 9q31.2 [SNP rs10512344]), specifically in a region previously linked to age of first menstruation. Further evaluation in the additional cohorts showed further associations with constipation-predominant IBS (IBS-C; P = .015) and harder stools (P = .0012), again in women only.
Functional annotation of the SNP in question on chromosome 9 revealed eight candidate genes, including one that is mutated in patients with familial dysautonomia, the investigators noted. These findings support further study on the role of sex hormones and autonomic dysfunction in IBS, they concluded. – by Adam Leitenberger
Disclosures: The authors report no relevant financial disclosures.