rs2922126 — GHSR GHSR A/G (rs2922126)

The Hunger Hormone's Receptor: When GHSR Expression Tips the Balance

Every time your stomach empties, it sends a chemical distress signal — a 28-amino-acid peptide called ghrelin — up the bloodstream and into the brain. Ghrelin¹¹ Ghrelin
The "hunger hormone," secreted primarily by the stomach fundus before meals and suppressed after eating. Rises during caloric restriction and after weight loss. docks onto its receptor, GHSR-1a (growth hormone secretagogue receptor type 1a), triggering appetite and promoting fat storage. But ghrelin does far more than tell you it's time to eat. GHSR-1a is also expressed in the brain's mesolimbic reward circuit²² mesolimbic reward circuit
Dopaminergic pathways connecting the ventral tegmental area to the nucleus accumbens, mediating motivation and pleasure responses to food, drugs, and other rewards., where it amplifies the desirability of food and drives motivated eating beyond simple caloric need. rs2922126 sits roughly 2 kilobases upstream of GHSR and influences the regulatory region that controls how much receptor is produced.

The Mechanism

rs2922126 is an upstream regulatory variant³³ upstream regulatory variant
Located ~2 kb before the GHSR transcription start site, within the promoter/proximal regulatory region that controls GHSR gene expression. — not a coding change, so the ghrelin receptor protein sequence is identical in all genotypes. The A allele is thought to alter transcription factor binding at the GHSR promoter, potentially shifting baseline receptor expression levels. Higher GHSR expression would amplify ghrelin signaling: stronger pre-meal hunger signals, increased food-reward sensitivity, and enhanced fat storage signaling. Nearby GHSR promoter variants with better-characterized function — particularly rs490683, which disrupts a nuclear factor 1 (NF-1) binding site — show that altered transcription factor access at this promoter⁴⁴ altered transcription factor access at this promoter
Mager et al. 2008 demonstrated that the rs490683-GG genotype with an intact NF-1 site shows increased GHSR promoter activity in reporter assays. has measurable metabolic consequences. rs2922126 likely operates through a similar mechanism, though its specific transcriptional effect has not been directly characterized.

The Evidence

The primary evidence for rs2922126 comes from a 2008 case-control study by Li et al.⁵⁵ Li et al.
Ghrelin receptor gene polymorphisms are associated with female metabolic syndrome in Chinese population. Chinese Medical Journal, 2008. enrolling 698 metabolic syndrome patients and 762 controls in China (total N=1,460). In women, the A/A genotype was associated with metabolic syndrome (OR 1.41, 95% CI 1.03–1.94), increased waist circumference (OR 1.75, 95% CI 1.26–2.42), and elevated fasting blood glucose (OR 1.49, 95% CI 1.07–2.06). These associations were not observed in men, pointing to a sex-hormone-mediated interaction between ghrelin signaling and central adiposity.

A 2013 prospective study by Yan et al.⁶⁶ Yan et al.
Adiposity, inflammation, genetic variants and risk of post-menopausal breast cancer findings from a PRoBE design approach. SpringerPlus, 2013. (180 cases, 732 controls) found that A/A homozygotes had a protective association against post-menopausal breast cancer (OR 0.4, 95% CI 0.18–0.89, p=0.02). This finding may reflect ghrelin's complex relationship with adipose tissue and estrogen signaling in post-menopausal women, though replication is needed before clinical weight is assigned to this result.

Null results also inform the picture. A longitudinal study of 1,362 children Riedl et al.⁷⁷ Riedl et al.
GH secretagogue receptor gene polymorphisms are associated with stature throughout childhood. European Journal of Endocrinology, 2012. found no association between rs2922126 and height or BMI across a 10-year follow-up, and a 2021 case-control study Tabaeian et al.⁸⁸ Tabaeian et al.
NAFLD case-control study, N=310. Journal of Gastrointestinal and Liver Diseases, 2021. found no association with non-alcoholic fatty liver disease. A systematic review Ghalandari et al.⁹⁹ Ghalandari et al.
Review of 24 GHRL/GHSR case-control studies. Int J Endocrinol Metab, 2015. concluded that the overall evidence across GHRL/GHSR polymorphisms and obesity is inconclusive. The metabolic syndrome signal from Li et al. has not been widely replicated in European or African ancestry populations.

Practical Actions

The A allele's primary actionable signal is elevated abdominal adiposity risk in women, mediated through amplified ghrelin/GHSR appetite signaling. Because GHSR drives hunger at the pre-meal level and amplifies food reward signals, targeted strategies that blunt pre-meal ghrelin spikes — rather than generic caloric restriction — are most aligned with the mechanism. High-protein meals are particularly effective at suppressing ghrelin compared to carbohydrate-matched meals, and distributing protein intake across three meals (rather than concentrating it at dinner) gives the most sustained pre-meal ghrelin suppression. For women with A/A genotype, waist circumference and fasting glucose are the most relevant biomarkers to track given the Li et al. findings.

Interactions

GHSR promoter variants rs490683 and rs9819506, studied by Mager et al. 2008 in the Finnish Diabetes Prevention Study, showed associations with body weight and glucose metabolism respectively. rs490683 has direct functional evidence (NF-1 binding site disruption) and may compound with rs2922126 if both variants shift GHSR expression in the same direction. rs572169, studied by Gueorguiev et al. 2009, was associated with obesity (OR 1.73, p=0.007) in an additive model — this is a distinct GHSR variant whose interaction with rs2922126 has not been studied. All four variants are within or near the GHSR promoter/upstream region and may tag related regulatory haplotypes.