Another three patients (2 males, 1 female) carried X-linked variants in COL4A5. The full clinical picture of Alport syndrome was not present in any of those patients and only two individuals (one with a COL4A3 and one with a COL4A5 variant) displayed hearing loss as the most common extrarenal manifestation of COL4-related disease. This evidence concerns the gene COL4A3 and Alport syndrome.