1. Clinical and Molecular Genetics
Unit, UCL Institute of Child Health, University College London, Guilford Street, London, WC1N 1EH, U.K.
2. Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, Queen
Square, London, WC1N 3BG, U.K.
3. Genzyme Corporation, 1 The Mountain Road,
Framingham, Massachusetts 01701, United States
4. Enzyme and Metabolic Unit, Chemical
Pathology, Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, U.K.