The human hCLCA1 and its murine ortholog mCLCA3 are members of the CLCA (calcium-activated chloride channel regulator) family with a well established role in inflammatory airway diseases with increased mucus production such as asthma, cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) [1]–[4]. The gene discussed is CLCA1; the disease is cystic fibrosis.