Cadherin related family member 3

The exact physiological role of CDHR3 is not known, but as the CDHR3 protein is expressed in epithelial tissues and has six extracellular cadherin domains plus a short transmembrane segment, it is believed to be related to the function of similar cadherins which function in cell adhesion and cell-to-cell signaling.[7] Two single-cell RNA expression studies furthermore found CDHR3 to be highly selectively expressed in ciliated epithelial cells, compared to other cell types in the respiratory epithelium, and thereby to be a marker for ciliated cells in respiratory airway tissue.[10][11]

A nonsynonymous mutation in CDHR3 at rs6967330 (C529Y) was at first found to be associated with severe asthma exacerbations in early childhood, with genome-wide significance. Functional experiments further indicated that this gene polymorphism leads to increased surface expression of the CDHR3 protein.[7] A subsequent study found that CDHR3 is a probable receptor for rhinovirus type C, a common form of rhinovirus.[8]

Recent studies furthermore found that CDHR3 gene variation is not associated with childhood bronchiolitis from respiratory syncytial virus (RSV) infection,[9] which resemble early asthma exacerbations as a phenotype. However, childhood bronchiolitis not caused by RSV infection, of which rhinovirus is often implicated, was associated with the CDHR3 gene variation. This is line with the results from a study on chronic rhinosinusitis, which often is associated rhinovirus infection, where CDHR3 gene variation also was found to be a strong risk factor.[12] Therefore, CDHR3 seems to causally linked to increased propensity for rhinovirus C infection.