Immunofluorescence studies showed that cilia of the respiratory cells obtained from patients with PCD caused by mutations in CCDC164 lacked GAS8 [154,155] and DRC3/LRRC48 (see below) [154] and that DRC3 is not present in respiratory cells obtained from patients with a mutation in GAS8 [157]. This evidence concerns the gene DRC4 and primary ciliary dyskinesia.