CFTR and primary ciliary dyskinesia: Cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) are two rare, chronic, recessive inherited diseases: CF is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), leading to impaired ion transport via this chloride channel with subsequent increased viscosity of the secretions of various surface epithelia of exocrine tissue especially in the respiratory tract [1, 2, 3].