COL4A6 and Alport syndrome: As DOL may be concomitant with Alport syndrome and all reported DOL-AS cases are associated with mutations in Collagen Type IV genes [5] (in particular with heterogeneous deletions spanning the COL4A5 and COL4A6 genes on the X chromosome) [2], we investigated the presence of copy number changes comprising the Collagen Type IV genes by using the SNP Chip data.