The present invention provides methods of treating Alport syndrome in a subject by the administration of an agent that can block the activation of RAC1/CDC42 members of the rho family of small GTPases. Such agents include, but are not limited to, the endothelin receptor antagonists such as bosentan and letairis and neutralizing antibodies to endothelin-1. Such administration prevents invasion of the glomerular capillary tufts by mesangial lamellipodial/filopodial processes, blocks mesangial process invasion abrogates the deposition of laminin 211 in the GBM, and prevents the activation of maladaptive expression of proteins known to contribute to glomerular disease progression.