The PCD is an abbreviation used for the primary cilia diskinesia disease. This condition result in the reduced motility of the cilia.
In respiratory tract, the cilia help the mucus to flow above the respiratory tract. In case, the cilia is damaged, or it is not able to move, then the mucus cannot move out of the respiratory tract and cause many respiratory abnormalities, such as congestion, infection, bronchitis, cough, short of breath, ear infections etc.