GSTM1 and Tangier disease: Prevalence of iron overload (Serum ferritin >200 μg/L) was 11 %, whereas that of anemia (Hb < 12 g/dL), iron deficiency (ferritin < 12 μg/L) and moderate folate deficiency (<5.9 ng/mL) was 3, 2 and 20.8 % respectively.