rs490683 — GHSR GHSR Promoter NF-1 Site Variant

Promoter variant in the ghrelin receptor gene that disrupts NF-1 transcription factor binding; the G allele preserves the binding site and elevates GHSR expression, increasing appetite drive and resistance to dietary weight loss intervention

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The Ghrelin Receptor Promoter Variant That Blunts Dietary Weight Loss

Ghrelin is the stomach's hunger signal — it rises before meals and drives appetite through the growth hormone secretagogue receptor (GHSR-1a)11 growth hormone secretagogue receptor (GHSR-1a)
The only known peripherally derived orexigenic receptor in humans; signals through both homeostatic hypothalamic circuits and mesolimbic reward pathways. How much GHSR protein is available in the brain determines how strongly ghrelin can drive eating behavior. rs490683 sits in the GHSR gene promoter, roughly 9 kb upstream of the coding sequence, at a site where the transcription factor nuclear factor 1 (NF-1)22 nuclear factor 1 (NF-1)
NF-1 proteins are a family of transcriptional activators that bind to TTGGCN₅GCCAA consensus sequences; they regulate expression of numerous genes involved in tissue homeostasis and energy metabolism normally binds and activates transcription. The rs490683-G allele preserves this binding site (the NF-1 consensus motif GCCA is intact); the C allele converts it to CCCA, disrupting binding and reducing promoter activity.

The Mechanism

Gel-shift (electrophoretic mobility shift assay) experiments from Mager et al. 200833 Mager et al. 2008
Finnish Diabetes Prevention Study group; N=507 overweight adults with impaired glucose tolerance; 3-year lifestyle intervention demonstrated that nuclear proteins bind to the G-allele sequence with 745% higher affinity than to the C-allele sequence. Reporter assays in Matzko et al. 201244 Matzko et al. 2012
Bariatric surgery cohort at Geisinger Clinic; N>650 RYGB patients followed 30 months confirmed that the CC genotype (both alleles disrupting NF-1 binding) reduces GHSR promoter activity by approximately 20% compared to the GG genotype. The result is a measurable difference in ghrelin receptor density: GG individuals express more GHSR in appetite-regulating brain regions, making them more sensitive to circulating ghrelin and creating a stronger biological pull toward eating during energy restriction.

The Evidence

The Finnish Diabetes Prevention Study55 Finnish Diabetes Prevention Study
507 overweight adults with impaired glucose tolerance randomized to intensive lifestyle intervention vs. control; 3-year follow-up; rs490683 was one of 7 GHSR variants genotyped found that rs490683-CC individuals showed the highest weight loss in the entire study population (p=0.032). The association extended to glucose metabolism: CC carriers maintained lower two-hour plasma glucose levels compared to CG heterozygotes (p=0.020) through the follow-up period. This functional SNP was the strongest GHSR variant in the study in terms of metabolic and weight outcomes.

Surgical validation came from a 650-patient RYGB cohort66 650-patient RYGB cohort
Roux-en-Y gastric bypass patients at Geisinger Health System; 30-month post-surgical follow-up; genotyped for 4 GHSR promoter variants where CC genotype again predicted the most weight loss post-operatively (additive model p=0.011, dominant model p<0.0097). The consistency across lifestyle intervention and bariatric surgery settings strengthens the causal interpretation.

The most recent and most direct test used a meal-replacement hypocaloric diet77 meal-replacement hypocaloric diet
N=96 obese adults (BMI>35); normocaloric hyperproteic formula twice daily for 12 weeks; Spanish population: non-G-allele carriers (CC genotype) lost an average of 8.5 kg vs. only 2.6 kg in G-allele carriers (p=0.01), representing a 3.3-fold difference in weight loss response to the same dietary intervention. Fat mass loss (-7.7 vs -2.6 kg), waist circumference reduction (-7.2 vs -2.9 cm), fasting glucose change (-12.1 vs -3.1 mg/dL), and insulin reduction (-10.8 vs -3.9 IU/L) all followed the same pattern. G-allele carriers also consumed significantly more calories, carbohydrates, fats, and proteins during the dietary intervention period, consistent with elevated ghrelin receptor signaling overriding dietary restraint.

Practical Actions

For GG individuals (the majority of the population), higher baseline GHSR expression means that ghrelin signaling is stronger during caloric restriction — the biological pull toward eating is more powerful and more persistent than in CC carriers. This does not mean dietary interventions cannot work; it means they face a genuine biological headwind. Strategies that reduce ghrelin levels most effectively — high-protein meals, resistance training, adequate sleep — take on added importance. Monitoring weight response to dietary interventions and adjusting protocol when responses are modest helps GG individuals find what works rather than attributing poor results to personal failure.

For GC heterozygotes, one functional copy of the NF-1 site remains intact, producing an intermediate expression level and intermediate intervention response.

CC carriers represent the minority who derive the greatest benefit from dietary restriction programs and should expect above-average weight loss responses to structured interventions.

Interactions

rs490683 sits in the same GHSR promoter haplotype block as rs2922126 and rs9819506, which are also on the platform. Carriers of multiple GHSR promoter risk variants may experience compounding effects on ghrelin receptor expression beyond what any single variant predicts. The ghrelin ligand side of the system is covered by rs696217 (GHRL Leu72Met), which affects postprandial ghrelin suppression; individuals carrying both impaired ghrelin suppression (rs696217 T allele) and elevated ghrelin receptor expression (rs490683 GG) may face additive appetite dysregulation affecting both the ligand level and the receptor sensitivity simultaneously.

Genotype Interpretations

What each possible genotype means for this variant.

CC Disrupted NF-1 Site — Reduced GHSR Expression Beneficial

Disrupted NF-1 binding on both alleles reduces GHSR expression and enhances dietary weight loss response

You carry two copies of the C allele, the rarest genotype — roughly 8% of people share this result. The C allele converts the NF-1 transcription factor binding site in the GHSR promoter from the consensus motif GCCA to CCCA, disrupting NF-1 binding and reducing GHSR promoter activity by approximately 20% compared to GG carriers. With both copies disrupted, your ghrelin receptor expression is at its lowest, meaning circulating ghrelin has a weaker signal to drive appetite. In clinical trials, CC individuals consistently show the best dietary weight loss responses: 8.5 kg vs. 2.6 kg on the same meal-replacement diet (de Luis et al. 2025), and the most weight loss after bariatric surgery (Matzko et al. 2012). Your biological headwind from ghrelin during caloric restriction is lower than average.

CG Intermediate Ghrelin Receptor Expression Intermediate

One intact NF-1 site produces intermediate GHSR expression and moderate appetite sensitivity during dietary restriction

The additive genetic model fits rs490683 best: each G allele adds one functional NF-1 site, each C allele removes one. CG heterozygotes therefore have one intact and one disrupted binding site, producing intermediate GHSR promoter activity. The 2008 Finnish DPS study and the 2012 RYGB study both tested additive models and found significant dose-response effects. CG individuals should expect meaningful but attenuated versions of the GG dietary challenges.

GG High Ghrelin Receptor Expression High Risk

Intact NF-1 binding site drives elevated GHSR expression and stronger appetite signaling during dietary restriction

The mechanism is transcriptional: gel-shift experiments demonstrated that nuclear proteins bind to the G-allele NF-1 site with 745% greater affinity than to the C-allele disrupted site. Reporter assays confirm that the GG genotype maintains approximately 20% higher GHSR promoter activity than the CC genotype. Higher GHSR density means greater sensitivity to circulating ghrelin — the hormonal pull toward eating is amplified during the caloric deficit periods that weight loss requires.

The effect replicates across dietary intervention (Finnish DPS, 507 participants), bariatric surgery follow-up (Geisinger RYGB cohort, 650+ patients), and meal-replacement diet studies (de Luis et al. 2025, 96 obese adults). Notably, G-allele carriers in the 2025 study consumed significantly more calories, carbohydrates, fats, and proteins at 12 weeks compared to CC individuals on the same prescribed diet, consistent with ghrelin-driven dietary non-adherence rather than intentional deviation.

The association with glucose and insulin is also present: G-allele carriers showed smaller improvements in fasting glucose (-3.1 mg/dL) and insulin (-3.9 IU/L) compared to CC individuals (-12.1 and -10.8, respectively) in response to hypocaloric dietary intervention.