They reported mutations in the known PCD genes as follows: RSPH9, CCNO, DNAAF5, RSPH4A, MCIDAS, and CCDC40 gene mutations in PCD patients with SPIs; CCDC151, DNAH11, CCDC40, DNAH5, and CCDC39 gene mutations in LD patients with SPIs; PKD1L1 and DNAAF5 gene mutations in LD patients; and RSPH9 and MCIDAS gene mutations in neonatal respiratory distress. Here, RSPH9 is linked to primary ciliary dyskinesia.