Compared to other renal cell types, ADPKD fibroblast cluster was the major source of 13 collagen subtypes, including COL1A1, COL1A2, COL3A1, COL4A1, COL4A2, COL5A1, COL5A2, COL6A2, COL6A3, COL12A1, COL14A1, COL15A1, and COL16A1 (Fig 1A). The gene discussed is COL4A1; the disease is autosomal dominant polycystic kidney disease.