Genetic polymorphisms in G-protein beta-3 subunit (GN▀3) and beta-2 adrenergic receptor (ADRB2) are associated with pain and gut hypersensitivity, which can overlap with gastroesophageal reflux disease (GERD).
Dr Gyawali and colleagues from Missouri, USA evaluated relationships between single nucleotide polymorphisms (SNPs) within GN▀3 and ADRB2 systems, and reflux symptom burden, GERD phenotypes from ambulatory reflux monitoring, and quality of life.
Symptomatic adults undergoing ambulatory reflux testing were recruited and phenotyped based on acid burden and symptom reflux association.
|Study subjects had higher anxiety scores compared to controls|
|Alimentary Pharmacology & Therapeutics|
Major esophageal motor disorders and prior foregut surgery were exclusions.
A comparison asymptomatic control cohort was also identified. Subjects and controls completed questionnaires assessing symptom burden on visual analog scales, short-form health survey-36 (SF-36), and Beck Anxiety and Depression Inventories (BAI and BDI).
Genotyping was performed from saliva samples, and 6 SNPs selected from each of the 2 genes of interest were compared.
The research team found that saliva from 151 study subjects, and 60 control subjects had sufficient genetic material for genotyping.
Study subjects had higher symptom burden, worse total and physical health, and higher anxiety scores compared to controls.
The team noted that tested SNPs within ADRB2 were similar between study subjects and controls.
Study subjects with recessive alleles in 3 GN▀3 SNPs (Rs2301339, Rs5443, and Rs5446) had worse symptom severity, worse mental health, and higher depression scores despite no associations with GERD phenotypes or reflux metrics.
Dr Gyawali's team concludes, "Genetic variation within GN▀3 predicts esophageal symptom burden and affect, but not esophageal acid burden or symptom association with reflux episodes."