Recognizing that the Hb-sTfR curve may represent a biological relationship, we acknowledge that thresholds for anemia based on detrimental health and functional outcomes (eg, exacerbation of underlying clinical conditions, reduced work capacity, fatigue, sleep disturbance, prematurity or low birth weight, or impaired child cognitive development) would advance the field.56,57,58,59,60. The gene discussed is GSTM1; the disease is anemia (phenotype).