rs11650680 — ORMDL3 ORMDL3 17q21 asthma susceptibility

ORMDL3 rs11650680 — A Protective Variant in the Asthma Susceptibility Haploblock

The chromosome 17q21 locus is the most consistently replicated genetic risk region for childhood-onset asthma. The locus spans a dense 130-kb regulatory haploblock containing six genes — IKZF3, ZPBP2, GSDMB, ORMDL3, LRRC3C, and GSDMA — and harbors a cluster of correlated variants that collectively regulate ORMDL3 expression in airway tissue and immune cells. rs11650680 is an intronic regulatory variant within this haploblock that was identified alongside rs7216389 in the original landmark GWAS¹¹ original landmark GWAS
Moffatt et al. Nature 2007, 994 childhood asthma cases vs 1,243 controls; rs11650680 and rs7216389 were among the top index SNPs at 17q21, p<10⁻¹². Unlike rs7216389 (where T is the risk allele), rs11650680 has the C allele as the risk allele and the T allele as the protective variant — a subtle but important distinction established by multiple meta-analyses.

The Mechanism

rs11650680 sits within an intron of the ORMDL3/GSDMB locus and functions as a regulatory eQTL²² regulatory eQTL
expression quantitative trait locus — a variant that alters nearby gene transcript levels without changing the protein sequence; rs11650680 modulates ORMDL3 and GSDMB expression in a C-allele-dose-dependent manner. The C allele is associated with higher ORMDL3 expression in airway epithelial cells and lymphoblastoid cell lines. Elevated ORMDL3 inhibits serine palmitoyltransferase, reducing de novo ceramide and sphingolipid synthesis in the airway epithelium. This sphingolipid deficit lowers T-cell activation thresholds, promotes Th2-skewed immune polarization, and activates the ATF6 branch of the unfolded protein response — collectively amplifying the eosinophilic airway inflammation that characterises asthma.

The T allele, by contrast, is associated with lower ORMDL3 expression³³ lower ORMDL3 expression
the T allele at rs11650680 reduces the C-allele-driven regulatory signal, producing less ORMDL3 mRNA in airway tissue and immune cells, and corresponds to the lowest asthma susceptibility at this locus. Carriers of one or two T alleles (CT and TT genotypes) produce less ORMDL3 and show correspondingly lower markers of airway eosinophilic inflammation than CC homozygotes.

The Evidence

The Shi et al. 2015 meta-analysis⁴⁴ Shi et al. 2015 meta-analysis
13 published case-control studies, 6,462 asthma cases and 7,357 controls; fixed-effects model; rs11650680 T allele significantly protective in dominant model (TT+CT vs. CC) established the asthma-protective role of the T allele across multiple populations. A second meta-analysis pooling 18 studies and 7,904 cases with 10,874 controls⁵⁵ pooling 18 studies and 7,904 cases with 10,874 controls
Wan et al. Human Immunology 2014, rs11650680 and rs12603332 T alleles both protective, consistent across Caucasian and Asian subgroups replicated the finding.

Population-specific data reveals important variation. A study of 315 Chinese children (315 asthma cases, 192 controls; Leung et al. Allergy 2009)⁶⁶ (315 asthma cases, 192 controls; Leung et al. Allergy 2009)
rs11650680 significantly associated with asthma diagnosis, atopy, and total plasma IgE levels (p=0.008–0.0002) in Chinese children; the CC risk genotype correlated with higher IgE burden and atopic sensitisation demonstrated that the rs11650680 locus affects not only asthma diagnosis but also atopic sensitisation and IgE production — linking the variant to the broader Th2-driven atopic phenotype beyond asthma alone.

In Japanese women, the CT heterozygous genotype was significantly inversely associated with asthma⁷⁷ CT heterozygous genotype was significantly inversely associated with asthma
Miyake et al. DNA Cell Biol 2014, 202 asthma cases and 1,290 controls in the KOMCHS cohort; CT vs. CC OR 0.67 (95% CI 0.46–0.96); effect was specific to adult-onset asthma, consistent with the meta-analysis direction. Separately, Acosta-Perez et al. 2012⁸⁸ Acosta-Perez et al. 2012
JACI, Puerto Rican and Mexican children; CC genotype associated with higher eosinophil-associated biomarkers and bronchial hyperresponsiveness, consistent with elevated ORMDL3-driven eosinophilic inflammation extended the finding to Latino populations.

Practical Implications

The CC genotype is the most common globally (~69%) and represents the reference state for this variant — but it also carries elevated asthma susceptibility. For CC individuals with asthma, the clinical picture is one of elevated eosinophilic airway inflammation driven by increased ORMDL3 activity: monitoring FeNO and blood eosinophil counts helps characterize the inflammatory endotype and guide treatment. For TT and CT carriers, the T allele provides partial to complete attenuation of the ORMDL3-driven airway inflammatory signal.

The rs11650680 signal is partially correlated with rs7216389 and rs12936231, and these SNPs likely tag overlapping but not fully redundant regulatory elements within the 17q21 haploblock. Carrying the protective T allele at rs11650680 does not eliminate risk conferred by other 17q21 variants, so the broader haploblock context matters for a complete risk picture.

Interactions

rs11650680 lies in strong LD with rs7216389 and rs12936231 within the same 17q21 haploblock, but the LD is incomplete — some individuals carry discordant genotypes across these three SNPs, suggesting partially independent regulatory signals. The combination of the CC genotype at rs11650680, the TT genotype at rs7216389, and the CC genotype at rs12936231 represents full engagement of the ORMDL3-overexpressing regulatory state; individuals with this haplotype combination have the highest ORMDL3 expression and the greatest airway inflammatory burden. The 17q21 locus also shows a well-documented inverse relationship with autoimmune disease risk⁹⁹ inverse relationship with autoimmune disease risk
the asthma-risk haplotype (high ORMDL3) is associated with lower risk of type 1 diabetes and Crohn's disease; the autoimmune-risk allele at rs2872507 is protective for asthma — reflecting the Th1/Th17 vs. Th2 immune axis trade-off.