Blood tests detected microcytic anemia in seven out of eight patients (median Hb 9.9 g/dL, IQR 1.95, range: 6.9–11.8; median MCV 71.9 fl, IQR 2.42, range: 66.8–74), that in one case required blood transfusion (#2); leukocyte and platelet blood count were normal in all patients. Here, GSTM1 is linked to microcytic anemia.