Five patients suffered severe gastrointestinal bleeding requiring blood transfusions (GDF-15 levels: 2172 pg/mL, 2255 pg/mL, 2297 pg/mL, 2333 pg/mL, and 8347 pg/mL), and one patient suffered macrohematuria due to urothelial carcinoma, not requiring a blood transfusion (GDF-15 level: 851 pg/mL). The gene discussed is GDF15; the disease is urothelial carcinoma.