A retrospective cohort study of 2,089 patients with non-dialysis CKD published in 2018 reported that high FGF23 levels were associated with anemia in a cross-sectional analysis; moreover, it showed an association between high serum FGF23 levels and an increased risk of developing anemia in a longitudinal analysis [10]. The gene discussed is FGF23; the disease is anemia (phenotype).