Sanfilippo D syndrome: Correction of glucosamine‐6‐sulphatase deficiency following fibroblast culture in chang's media

The de‐O‐sulphation of α‐linked glucosamine‐6‐sulphate residues in heparan sulphate requires a specific sulphatase, glucosamine‐6‐sulphatase, which has been shown to be deficient in tissues of Sanfilippo D, or mucopolysaccharidosis type IIID (MPS IIID), patients. MPS IIID fibroblasts cultured in Basal Eagle's medium supplemented with either fetal calf serum or heat‐inactivated fetal calf serum, MDCB or Ultraserg media had residual glucosarnine‐6‐sulphatase activities towards a heparin‐derived trisaccharide substrate, O‐(α‐N‐acetylglucosamine‐6‐sulphate)‐(1→4)‐L‐O‐(α‐iduronic acid‐2‐sulphate)‐(1→4)‐D‐O‐2,5‐anhydro [1‐³H]mannitol‐6‐sulphate, GlcNAc6S‐IdoA2S‐anM6S, which were less than 1 per cent of the normal range for fibroblasts cultured in Basal Eagle's medium supplemented with fetal calf serum. However, the glucosamine‐6‐sulphatase activities of MPS IIID fibroblasts grown in Chang's medium were similar to the activities in normal control fibroblasts which were cultured in Basal Eagle's medium. These results indicate that caution is required for prenatal diagnosis of MPS IIID patients using chorionic villi or amniotic cells cultured in Chang's medium.