Moreover, immunostaining of the liver showed an enrichment of SUMO1 (i.e., combination of free SUMO1 ligand and SUMO1-conjugated proteins) in the cystic epithelium of patients with ADPKD and ARPKD, as well as in PCK rats, compared to the biliary epithelium of healthy controls (Fig. 1C). The gene discussed is SUMO1; the disease is autosomal dominant polycystic kidney disease.