Among all candidate PCD-relevant genes, DNAH5 was the most prevalent disease-causing gene, occurring in 23.1% of all patients with PCD, compared to a previous study by Failly in which only 15% of 89 unrelated individuals of European origin with PCD were associated with DNAH5 and in a study by Hornef in which 28% of 109 individuals of European or North American origin with PCD carried mutations clustering within exons 34, 50, 63, 76, and 77, and no c.8383C > T variants were observed [20, 28]. This evidence concerns the gene DNAH5 and primary ciliary dyskinesia.