rs6967330 — CDHR3 C529Y

CDHR3 C529Y — The Rhinovirus-C Receptor Variant

CDHR3 (cadherin-related family member 3)¹¹ CDHR3 (cadherin-related family member 3)
A cell-surface adhesion molecule expressed exclusively on ciliated airway epithelial cells, including those lining the bronchi, trachea, nasopharynx, and middle ear is not just a structural protein — it is the receptor that rhinovirus-C (RV-C) uses to enter respiratory cells. RV-C is the most clinically severe of the three rhinovirus species, disproportionately responsible for childhood asthma exacerbations requiring hospitalization. The rs6967330 missense variant — a single nucleotide change that swaps cysteine for tyrosine at amino acid position 529 (C529Y) — dramatically alters how efficiently RV-C can dock onto and infect airway cells.

The tyrosine-529 form (the A allele, carried by roughly 17% of Europeans) makes CDHR3 a far more effective viral receptor: it localizes more densely on the cell surface and binds RV-C with approximately ten times the efficiency of the common cysteine-529 form. This variant exemplifies how a single amino acid difference can transform a structural protein into a viral susceptibility factor of substantial clinical significance.

The Mechanism

CDHR3 is expressed exclusively on ciliated airway epithelial cells²² ciliated airway epithelial cells
Ciliated cells line the respiratory tract and beat rhythmically to move mucus and trapped particles upward and out — they are also the primary entry point for RV-C. RV-C virions bind to the extracellular domain of CDHR3 (specifically the EC1 domain) as their obligate entry mechanism.

The C529Y substitution resides in the extracellular cadherin repeat region³³ extracellular cadherin repeat region
Cadherins use repeated structural domains (EC1–EC5) for binding; the EC1 domain is the virus contact surface identified by Watters & Palmenberg 2018 of the protein. The tyrosine at position 529 alters the protein's folding or glycosylation state in a way that increases its density at the apical cell surface. A landmark PNAS study found that cells transfected with the Y529 variant showed approximately 10-fold higher RV-C binding and progeny virus yields⁴⁴ landmark PNAS study found that cells transfected with the Y529 variant showed approximately 10-fold higher RV-C binding and progeny virus yields
Compared to cells expressing the common C529 form under identical infection conditions; the variant did not affect expression of other cadherin family members. Complementary knockout experiments confirmed that CDHR3 is the non-redundant entry receptor: eliminating CDHR3 expression reduced HRV-C infection of mucociliary epithelium by 80%⁵⁵ eliminating CDHR3 expression reduced HRV-C infection of mucociliary epithelium by 80%
Functional genomics study using airway organoids and CRISPR knockdown, published in JACI 2019.

Because CDHR3 is also expressed on ciliated epithelial cells lining the Eustachian tube⁶⁶ Eustachian tube
The channel connecting the nasopharynx to the middle ear — its ciliated lining is part of the same mucociliary apparatus that clears pathogens from the upper respiratory tract and middle ear, RV-C infections seeded by higher CDHR3-Y529 expression can ascend to trigger otitis media (middle ear infection) — explaining the multi-infection GWAS signals at this locus.

The Evidence

The strongest evidence comes from a GWAS of 1,173 children with recurrent severe asthma exacerbations and 2,522 controls, published in Nature Genetics⁷⁷ GWAS of 1,173 children with recurrent severe asthma exacerbations and 2,522 controls, published in Nature Genetics
Bønnelykke et al. 2014; phenotype specifically selected for early childhood asthma (ages 2–6) requiring emergency care — this phenotypic specificity may explain why the CDHR3 signal emerged when broader asthma GWAS missed it. The CDHR3 locus reached genome-wide significance, making it one of the top genetic determinants of severe childhood-onset asthma.

A 2025 pediatric study examining 297 rhinovirus-positive children found that carriers of the A allele (Y529) had nearly twice the risk of rhinovirus-C-induced wheezing compared to GG carriers⁸⁸ nearly twice the risk of rhinovirus-C-induced wheezing compared to GG carriers
OR 1.91, 95% CI 1.05–3.48, P = 0.033; dominant model; study of 129 HRV-C cases and 148 HRV-A controls from hospitalized children with acute respiratory infections. Notably, 56.67% of HRV-C-infected A-allele carriers experienced wheezing, versus a lower rate in GG carriers.

The connection to middle ear infections was established in a 2021 multi-ethnic family study showing that CDHR3 variants co-segregate with otitis media susceptibility in 257 families⁹⁹ CDHR3 variants co-segregate with otitis media susceptibility in 257 families
Exome sequencing of 407 US trios; the p.Cys529Tyr variant associated with altered middle ear microbiome and disease course. CDHR3 expression is present in ciliated middle ear epithelium and is downregulated following infection — consistent with viral exploitation of the receptor.

Mechanistically, recombinant EC1 domain fragments of CDHR3 competitively inhibit RV-C infection across multiple genotypes (C02, C15, C41, C45)¹⁰¹⁰ recombinant EC1 domain fragments of CDHR3 competitively inhibit RV-C infection across multiple genotypes (C02, C15, C41, C45)
Proof-of-concept for receptor-blocking as a therapeutic strategy; inhibitory fragments reduced infection across diverse RV-C strains in cell-based assays, confirming that CDHR3 is the non-redundant receptor and validating it as a potential therapeutic target.

Practical Actions

Carriers of the A allele (heterozygous AG or homozygous AA) have meaningfully higher risk of severe rhinovirus-C respiratory infections. Rhinovirus-C infections are not prevented by current influenza or COVID-19 vaccines — there is no licensed RV-C vaccine. The actionable strategy is reducing viral acquisition and supporting rapid immune clearance.

RV-C is transmitted primarily through direct contact (hands-to-face) and respiratory droplets. Hand hygiene is uniquely effective against rhinoviruses because, unlike influenza, rhinoviruses survive for hours on surfaces and are primarily acquired via hand-to-mucosa contact. This is a genotype-specific reason to be rigorous about hand hygiene during peak rhinovirus season (autumn and spring) — not generic advice, but a targeted risk-mitigation strategy for CDHR3-Y529 carriers who face ~10-fold higher cell-surface receptor availability.

For children with this variant who have recurrent wheezing, the CDHR3 genotype supports a clinical discussion about rhinovirus-C-triggered asthma phenotype and the potential role of early antiviral or anti-inflammatory intervention during respiratory infections. [Nasal zinc acetate lozenges | Zinc interferes with ICAM-1-mediated rhinovirus binding and has documented efficacy for rhinovirus infections, though data specific to RV-C are limited] have evidence for shortening rhinovirus illness duration.

Interactions

CDHR3-Y529 risk is compounded by co-inherited asthma susceptibility variants. The Bønnelykke GWAS also detected signals at GSDMB, IL33, and IL1RL1 — all operating through airway inflammatory pathways. Carriers of CDHR3 Y529 combined with IL33 or IL1RL1 risk variants face both heightened RV-C entry and amplified downstream inflammatory responses, potentially explaining the "two-hit" pattern of severe exacerbations in some children. The supervisor should consider a compound action for CDHR3 + IL33/IL1RL1 combinations if those SNPs are in the database.