COL4A3 and Alport syndrome: For instance, Alport syndrome (AS) is a progressive hereditary renal disease accompanied by sensorineural hearing loss and ocular abnormalities, caused by the pathogenic variants in the genes of COL4A3, COL4A4, and COL4A5 encoding type IV collagen α3, α4, and α5 chains, respectively (Nozu et al., 2020; Kashtan, 2021).