rs10195252 — GRB14/COBLL1

The Fat Geography Gene: How rs10195252 Routes Fat to Limbs or Viscera

Where your body stores fat matters as much as how much fat you carry. Two people with identical BMI can have entirely different metabolic risk profiles depending on whether their excess fat accumulates around their organs (visceral) or in their hips, thighs, and legs (peripheral). The rs10195252 variant in the intergenic region between GRB14 and COBLL1 on chromosome 2 is one of the most replicated genetic determinants of this fat routing — and its effects are substantially stronger in women than men.

GRB14 (Growth Factor Receptor-Bound Protein 14) is an adaptor protein that acts as a braking mechanism on the insulin receptor¹¹ adaptor protein that acts as a braking mechanism on the insulin receptor
GRB14 binds to the activated insulin receptor and inserts its BPS domain as a pseudosubstrate inhibitor, blocking downstream signaling. Higher GRB14 expression in adipose tissue means weaker insulin signaling in that depot, which in turn affects how efficiently fat is stored and mobilized there. COBLL1 (Cordon-Bleu WH2 Repeat Protein-Like 1) is the neighboring gene and shares part of the regulatory landscape; it too is associated with leptin, central obesity, and fasting insulin.

The Mechanism

rs10195252 sits in the intergenic region between GRB14 and COBLL1 and functions as an expression quantitative trait locus (eQTL)²² expression quantitative trait locus (eQTL)
An eQTL is a genetic variant that controls how much mRNA a nearby gene produces, without changing the protein's amino acid sequence for GRB14 in adipose tissue. The T allele drives higher GRB14 expression, particularly in visceral adipose tissue, which suppresses insulin signaling in the belly and promotes a pattern where fat moves toward central compartments and away from peripheral depots. The C allele is associated with lower GRB14 expression, allowing more robust insulin signaling in visceral fat — which has the paradoxical effect of facilitating fat storage in peripheral depots (hips, thighs, lower limbs) while leaving central fat accumulation less hormonally supported.

This means the C allele shifts the body's default fat routing toward gynoid (peripheral/lower-body) distribution³³ gynoid (peripheral/lower-body) distribution
Named for the pattern more common in women; associated with higher hip-to-waist ratio and fat deposition in thighs, buttocks, and lower legs. The T allele does the opposite — it shifts fat toward the android (central, visceral) pattern. This explains why the T allele increases waist-hip ratio (WHR) while the C allele decreases it.

The Evidence

The foundational study is the 2010 GIANT consortium meta-GWAS of 77,167 individuals⁴⁴ meta-GWAS of 77,167 individuals
Analysis across 32 separate genome-wide association studies; rs10195252 reached p = 5.9 × 10⁻¹⁵ for WHR adjusted for BMI, which identified rs10195252 as one of 13 new loci for waist-hip ratio. The GRB14 locus showed marked sexual dimorphism — the effect was substantially stronger in women than men — consistent with estrogen's role in modulating insulin signaling in adipose depots. A subsequent larger meta-analysis of 224,459 individuals⁵⁵ larger meta-analysis of 224,459 individuals
Shungin et al. 2015; linked adipose tissue biology and insulin signaling directly to fat distribution genetics confirmed the locus among those most strongly linking adipose insulin biology to body fat distribution.

A key functional study by Gruber et al. 2022⁶⁶ Gruber et al. 2022
n = 2,860 subjects with metabolic phenotypes; 560 subjects with adipose tissue gene expression measurements demonstrated that the T allele at rs10195252 was significantly associated with increased GRB14 mRNA in visceral adipose tissue and that this visceral GRB14 expression fully mediated the association between rs10195252 and HbA1c — connecting the genetic variant to real-world glucose regulation through an adipose tissue molecular pathway. Carriers of the T allele also showed higher triglycerides, higher fasting plasma glucose, and lower HDL cholesterol.

The connection to lipedema — a condition of disproportionate lower-body and limb fat accumulation predominantly in women — was established by a UK Biobank GWAS of 24,450 cases⁷⁷ UK Biobank GWAS of 24,450 cases
Lörcher et al. 2022; GRB14/COBLL1 locus replicated in independent clinical lipedema cohort (130 cases); p = 2.3 × 10⁻³. The locus was associated specifically with leg fat percentage, independently of hip circumference — meaning the effect is not simply driven by large hips but by fat throughout the lower limbs. This finding directly implicates C-allele-driven peripheral fat routing in lipedema pathophysiology.

Practical Implications

For individuals carrying one or two copies of the C allele, the body's fat storage preference runs toward the lower limbs and hips. This does not cause lipedema on its own — lipedema is multifactorial — but it represents a significant component of the genetic predisposition. The insulin signaling pattern in visceral adipose may be more robust (lower GRB14 expression), but peripheral fat depots respond to insulin more readily, making them preferential storage sites.

Two actionable implications follow: First, interventions that transiently lower insulin (reducing carbohydrate intake, time-restricted eating) can partially redirect fat mobilization away from the peripheral depots where GRB14 expression is lower and insulin sensitivity is higher. Second, monitoring waist-hip ratio and lower-limb circumference provides more informative tracking data than scale weight alone, since weight loss may unevenly reduce peripheral fat stores.

The T-allele pattern (higher central fat tendency, higher GRB14 visceral expression) carries its own concern: association with higher HbA1c, triglycerides, and fasting insulin suggests elevated cardiometabolic risk independent of BMI.

Interactions

The GRB14/COBLL1 locus interacts with other fat distribution variants on chromosome 2 and overlapping GWAS signals. The nearby rs6738627 in COBLL1⁸⁸ rs6738627 in COBLL1
A second index SNP at this locus with partially independent effects on body fat percentage and leptin levels is separately associated with body fat percentage independently of BMI. Both rs10195252 and rs6738627 show overlapping metabolic associations (triglycerides, glucose, leptin), suggesting the entire locus regulates adipose tissue insulin signaling and fat partitioning as a functional unit.

Supervisor note — candidate compound interaction: The C allele at rs10195252 (peripheral fat routing) and the A allele at rs9939609 (FTO, increased adiposity/appetite) combine in a pattern where both fat volume and fat routing tilt unfavorably — higher total fat mass directed preferentially to limbs and lower body. Published evidence for this specific combination is not available, but both loci are independently established for fat distribution traits and the combined phenotype (excess peripheral fat mass) is clinically meaningful for lipedema risk assessment. A compound monitoring recommendation covering both variants would be appropriate if supported by future data.