Specific staining of collagen type IV (Col IV), which is increased in renal fibrosis, revealed higher extracellular deposition of Col IV in mice lacking Clcn5 (Clcn5+/− and Clcn5−/−) compared with Clcn5+/+ mice (1.14 μm versus 0.81 μm, P < 0.01) (Fig 7A and C), reproducing the results from our CLCN5 KD cells. The gene discussed is CLCN5; the disease is renal fibrosis.