GSTM1 and Scheie syndrome: In this study, heart valve replacement (metallic valve) was performed in six patients with MPS I. Their urinary GAG concentration was higher in the heart valve replacement group (p < 0.026), with serum iron (p < 0,028), Hb (p < 0.009), hematocrit(p < 0.002) and MCV (p < 0.032) levels being statistically significantly low.