If a group of metabolic paediatricians had been asked 10 years ago which disorders they thought would be the most treatable at the start of the new millennium, very few would have mentioned lysosomal storage disorders (LSDs). The early onset, progressive nature, and tendency to involve the CNS have always been regarded as major hurdles to effective treatment. However, the final decade of the 20th century has seen developments in organ transplantation, enzyme replacement therapy (ERT), and gene transfer so that curative treatment for at least some of these disorders is no longer a distant goal.