A Study of Intrathecal Enzyme Therapy for Cognitive Decline in MPS I

For the treatment group, intrathecal rhIDU injections will consist of 3 cc of Aldurazyme® (laronidase) (approximately 1.74 mg) diluted with 6 cc of Elliotts B® solution for a total injection of 9 cc. The diluted enzyme will be administered via a lumbar puncture (IT) on day 0 after baseline assessments. IT injections will be repeated on days 30, 60, and 90. The subsequent doses will be administered at 3-month intervals for a total of 10 doses during the two-year period. Control patients will not receive treatment, lumbar puncture, or placebo, but will undergo all other study procedures and assessments during year one. Control patients will then enter a treatment phase consisting of four IT doses at 3-month intervals.