DRC1 and primary ciliary dyskinesia: In 105 Japanese patients with recurrent sinopulmonary infection, initially diagnosed with DPB, and 37 patients with recurrent airway infection diagnosed in adulthood, the deletion allele of DRC1 or CCDC164, recently recognized as a pathogenic PCD gene variant, was searched using a multiplexed PCR‐based method, and the deletion breakpoints and other variants around the gene were determined by Sanger sequencing and targeted resequencing.