Few studies examined the impact of low-normal hemoglobin (Hb) levels and anemia on development of ESRD, despite the fact that low Hb levels per se may contribute to the progression of CKD to ESRD [3,4], while Hb decline and anemia may occur as a consequence of CKD even at early stages [5]. The gene discussed is GSTM1; the disease is anemia (phenotype).