rs7130588 — LRRC32

LRRC32 (GARP) — The Tolerance Gate at the 11q13.5 Locus

On chromosome 11q13.5 sits a stretch of regulatory DNA that, in people carrying the G allele at rs7130588, subtly tips the balance of the immune system toward allergic reactivity. The gene controlled by this region, LRRC32, encodes GARP (Glycoprotein A Repetitions Predominant)¹¹ GARP (Glycoprotein A Repetitions Predominant)
GARP is a surface receptor expressed on activated regulatory T cells (Tregs); it docks latent TGF-β on the Treg cell surface, where TGF-β can be released in a controlled fashion to suppress nearby immune cells — a critical molecule in the suppressive machinery of regulatory T cells (Tregs). When GARP function is altered, the Treg-mediated braking on allergic inflammation weakens, and atopic diseases become more likely.

The Mechanism

GARP is a transmembrane receptor expressed exclusively on activated Tregs (and platelets). Its core job is to anchor the latent TGF-β1 complex — the "sleeping" form of this immunosuppressive cytokine — on the cell surface. Surface-tethered latent TGF-β can be activated locally, delivering targeted suppression to nearby effector T cells, dendritic cells, and B cells without flooding systemic circulation with active TGF-β. This spatial precision is what makes GARP-mediated tolerance so important: it allows Tregs to dampen Th2-skewed responses in peripheral tissues like the airway and skin while leaving systemic immunity intact.

rs7130588 lies in a regulatory (non-coding) region approximately 10 kb upstream of the LRRC32 promoter. A closely linked causal candidate, rs6592645 (in complete linkage disequilibrium with rs7130588), falls within an enhancer element that physically loops to the LRRC32 promoter. Luciferase reporter assays²² Luciferase reporter assays
A standard lab test where the regulatory region controls a bioluminescent reporter gene; more light = more transcriptional activity from that sequence confirmed that the A allele of rs6592645 (the rs7130588-G-linked haplotype) drives higher enhancer activity than the G allele, via preferential binding of the transcription factor TCF3. LRRC32 mRNA levels are correspondingly elevated in lung tissue of asthma patients in a genotype-dependent manner.

The counterintuitive implication: higher GARP expression might be expected to enhance Treg suppression and protect against allergy. The biology, however, is more complex. Elevated GARP may alter the balance between membrane-bound and soluble GARP isoforms, the ratio of latent-to-active TGF-β at the Treg surface, or Treg activation thresholds in ways that impair rather than enhance tolerance in allergic tissue contexts. The net clinical observation is unambiguous: the G-risk allele associates with more atopic disease, not less.

The Evidence

The sentinel discovery came from Ferreira et al. in the Lancet³³ Ferreira et al. in the Lancet
Australian Asthma Genetics Consortium GWAS, 57,800 participants including 2,669 asthmatics and 4,528 controls in the discovery stage plus 25,358 in replication (2011): rs7130588 reached genome-wide significance (OR 1.09, p=1.8×10⁻⁸) for overall asthma, with a stronger signal for atopic asthma specifically (OR 1.33 for atopic status among asthmatics, p=7×10⁻⁴). The authors concluded the locus "directly increases the risk of allergic sensitisation which, in turn, increases the risk of subsequent development of asthma."

The GWAS Catalog records two subsequent associations at this variant: OR 1.29 (95% CI 1.20–1.38, p=4×10⁻¹³) and OR 1.242 (95% CI 1.17–1.31, p=2×10⁻⁹) in larger replication efforts, confirming and strengthening the original signal.

Beyond asthma, the LRRC32 locus is a shared risk locus across the atopic triad. Weidinger et al.⁴⁴ Weidinger et al.
GWAS of childhood atopic dermatitis, 1,563 European cases and 4,054 controls with replication in a second cohort (2,286 cases, 3,160 controls) (2013) confirmed the proximal LRRC32 region at genome-wide significance for atopic dermatitis. Most tellingly, Marenholz et al.⁵⁵ Marenholz et al.
Meta-analysis of 12 populations, 2,428 cases of the "atopic march" phenotype (eczema followed by asthma), 17,034 controls (2015) confirmed LRRC32/C11orf30 as one of seven loci driving the progression from infantile eczema to childhood asthma — the classic atopic march. The locus sits at the intersection of all three major atopic phenotypes: eczema, allergic asthma, and (via the atopic march pathway) allergic rhinitis.

The functional direction — that GARP is genuinely causal, not just a passenger — is supported by a humanized mouse model study⁶⁶ humanized mouse model study
Mice engrafted with human PBMCs from birch-pollen sensitized donors; treatment with soluble GARP reduced airway hyperresponsiveness, neutrophil and macrophage influx, and mucus-producing goblet cells; effect abolished by anti-TGF-βRII antibody in which exogenous soluble GARP reduced allergic airway inflammation in a TGF-β receptor-dependent manner. Separately, a clinical study found that children who outgrow food allergy have significantly higher GARP expression on peripheral blood mononuclear cells compared with those who do not (p=0.005), establishing GARP as a marker — and potentially a driver — of immune tolerance acquisition.

Practical Actions

The G allele's risk is primarily expressed in the context of atopic sensitization. G-allele carriers who already have one atopic condition (eczema, food allergy, or allergic rhinitis) face meaningfully elevated risk of asthma development — the atopic march phenotype. Early allergist evaluation and proactive management of existing atopic conditions can interrupt this progression. Aeroallergen immunotherapy, which directly raises functional Treg activity and GARP expression, is the intervention most biologically aligned with this locus's mechanism.

For GG homozygotes (approximately 11% of people of European descent), the cumulative risk elevation is additive and warrants baseline spirometry and exhaled nitric oxide (FeNO) measurement to detect subclinical airway inflammation before clinical asthma develops.

Interactions

The LRRC32 locus partially overlaps with C11orf30 (EMSY), which is itself an independent asthma and eczema risk gene; fine-mapping distinguishes the two signals, but in population data they travel together on 11q13. rs6592645, the likely causal variant in full LD with rs7130588, is the preferred candidate for functional follow-up. rs3781700 (nearby in this region) has been identified with OR ~1.054 for atopic dermatitis in large GWAS, representing additional independent variation at the locus.

Compound effects with PTPN22 rs2476601 (R620W), a T-cell activation threshold variant, are plausible given both genes influence regulatory T cell function, but no formal gene-gene interaction study has yet been published.