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

Abstract

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.

• Authors: Ann E Almazar, Joseph Y Chang, Joseph J Larson, Elizabeth J Atkinson, G Richard Locke, Nicholas J Talley, Yuri A Saito
• Journal: Journal of clinical gastroenterology (J Clin Gastroenterol) Vol. 53 Issue 6 Pg. e227-e231 (07 2019) ISSN: 1539-2031 [Electronic] United States
• PMID: 29912753 (Publication Type: Journal Article)

Chemical References

• Lactase
• MCM6 protein, human
• Minichromosome Maintenance Complex Component 6

Topics

• Adolescent
• Adult
• Aged
• Breath Tests (methods)
• Case-Control Studies
• Female
• Genotype
• Humans
• Irritable Bowel Syndrome (genetics, physiopathology)
• Lactase (genetics)
• Lactose Intolerance (diagnosis, epidemiology, genetics)
• Male
• Middle Aged
• Minichromosome Maintenance Complex Component 6 (genetics)
• Polymorphism, Single Nucleotide
• Prevalence
• Self Report
• Surveys and Questionnaires
• Young Adult