We previously reported (14) that mothers of infants in the MMN and LNS groups, who consumed supplements with a lower iron content (20 mg/d) than did those in the IFA group (60 mg/d), had a lower mean Hb concentration, lower iron status (higher mean ZPP and plasma transferrin receptor), and a higher prevalence of anemia at 36 weeks of gestation. The gene discussed is GSTM1; the disease is anemia (phenotype).