Overlapping Clinical Phenotypes in Patients with Primary Ciliary Dyskinesia or Activated Phosphoinositide 3-Kinase Delta Syndrome

Primary ciliary dyskinesia and activated phosphoinositide 3-kinase delta syndrome type 1 present similarly, with recurrent respiratory infections and reduced nasal nitric oxide levels. When diagnostic confirmation of primary ciliary dyskinesia with genetic testing and/or ciliary electron microscopy is inconclusive, activated phosphoinositide 3-kinase delta syndrome type 1 and other inborn errors of immunity must be investigated.