Tanaka et al. found that USAG-1 may enhance the expression of MMP-12 in the glomerulus by inhibiting the inhibitory effect of BMP7 and aggravate the progression of glomerular disease in Alport syndrome, while the genetic ablation effect of USAG-1 greatly reduces disease progression in Col4a3–/– mice (a model of human Alport syndrome) and preserves kidney function [30]. Here, COL4A3 is linked to Alport syndrome.