This trial is studying mucus clearance in people with a disease called Primary Ciliary Dyskinesia (PCD). It will compare different groups of people with PCD, some of which have mutations associated with a milder clinical phenotype. The hypothesis is that subjects with PCD caused by mutations in the milder group will have a lower, but significant, rate of mucus clearance, while patients with mutations in genes in the more severe group will have a complete absence of mucus clearance.