Electron micrographs showing defects associated with primary ciliary dysfunction

Electron micrographs of nasal cilia from patients with primary ciliary dyskinesia (PCD) illustrating dynein defects. Panel A illustrates ultrastructure of a normal cilium from nasal epithelium of a healthy, clinically unaffected subject. The adjacent panels are from three different PCD patients. Panel B illustrates absence of the inner and outer dynein arms; Panel C shows absence of the outer dynein arms only; and Panel D shows absence of the inner dynein arms only.