In the largest series to date, an analysis of 5,834 kidney transplant recipients at 10 European outpatient transplant clinics detected anemia in 42% of patients based on the American Society of Transplantation anemia guidelines (Hb ≤ 13.0 g/dL in males and ≤ 12.0 g/dL in females) [6]. The gene discussed is GSTM1; the disease is anemia (phenotype).