COL4A4 and Nephropathy: Finally, for the heterozygous COL4A3/COL4A4 pathogenic variants carriers, our data are consistent with a recent systematic review on COL4A3/COL4A4 nephropathy (Matthaiou et al., 2020), in which the rate of ESRD is 15.1% at a mean age of 52.8 years.