Primary ciliary dyskinesia caused by a large homozygous deletion including exons 1-4 of DRC1 in Japanese patients with recurrent sinopulmonary infection.

PCD caused by the DRC1 defect is not readily identified by either high-speed video-microscopy or ciliary ultrastructure analysis, posing significant difficulties in reaching a correct diagnosis without the aid of genetic tests. Careful investigation of the causes of sinopulmonary diseases is warranted in Asian populations.