Comparison of Lactase Variant MCM6-13910 C>T Testing and Self-report of Dairy Sensitivity in Patients with Irritable Bowel Syndrome

Ann E. Almazar, Joseph Y. Chang, Joseph J. Larson, Elizabeth J. Atkinson, G. Richard Locke, Nicholas J. Talley, Yuri A. Saito

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Goals:To evaluate agreement of MCM6-13910 with self-report of dairy sensitivity (DS) and lactose hydrogen methane breath test (LHMBT) results in subjects with irritable bowel syndrome (IBS).Background:IBS is a functional gastrointestinal disorder with symptoms including abdominal pain, variable bowel habits, and bloating. Adult patients with lactose malabsorption may present with similar symptoms. Patients with lactose malabsorption have a lactase nonpersistent (LNP) phenotype. Recent studies found 2 single nucleotide polymorphisms associated with LNP: G/A-22018 and C/T-13910.Study:Genotyping the MCM6-13910 variant of LNP in 538 IBS patients and 317 controls (without IBS). Subjects completed questionnaires pertaining to gastrointestinal problems and dietary consumption, with charts abstracted.Results:Self-reported DS was higher in IBS (45%) than controls (9.8%, odds ratio=6.46, P<0.001). The C/C-13910 genotype was similar in IBS cases and controls, 81 (15.1%) and 47 (14.8%). Among subjects reporting DS, 49 (18.0%) had the C/C genotype. Overall agreement between genotype and self-reported DS was 0.06 in IBS and 0.07 in controls. There were 20 subjects with LHMBT results; 3 had positive results, 17 were negative. LNP genotypes were found in all 3 of positive LHMBT results; 16 had negative LHMBT among the 17 who were lactase persistent. Agreement between C/C-13910 genotype and LHMBT was excellent with κ-statistic of 0.83 (0.50-1.00).Conclusions:In IBS patients, self-report of lactose intolerance are highly prevalent but are a poor indicator of underlying C/C-13910 genotype. LHMBT had excellent agreement with C/C-13910 genotype.

Original languageEnglish (US)
Pages (from-to)E227-E231
JournalJournal of clinical gastroenterology
Issue number6
StatePublished - Jul 1 2019


  • dairy sensitivity
  • irritable bowel syndrome
  • lactase

ASJC Scopus subject areas

  • Gastroenterology


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