As expected, both jck-MMP9+/+ and jck-MMP9-/- polycystic mice developed renal failure but it was more pronounced in jck-MMP9 deficient mice, as attested by the significantly higher serum creatinine values in 1- and 4- month old jck-MMP9-/- mice compared to their jck-MMP9+/+ littermates (Fig 2A). The gene discussed is MMP9; the disease is kidney failure.