Author Affiliations: Division of Biochemical Diseases, Department of Pediatrics, British Columbia Children's Hospital, Vancouver, Canada (Mercimek-Mahmutoglu S, Stoeckler-Ipsiroglu S); Department of Orthopedics, British Columbia Children's Hospital, Vancouver, Canada (Reilly C); Division of Cardiology, Department of Pediatrics, British Columbia (Human D); Biochemical Genetics Laboratory, Department of Pathology and Laboratory Medicine, British Columbia Children's Hospital, Vancouver, Canada (Waters PJ)

Corresponding Author: Saadet Mercimek-Mahmutoglu, MD, FCCMG, British Columbia Children's Hospital, Division of Biochemical Genetic Diseases, Room K3-208, ACB, 4480 Oak Street, Vancouver, B.C., Canada V6H 3V4 (Tel: 604-875-2628; Fax: 604-875-2349; Email: smahmutoglu@cw.bc.ca)

doi:10.1007/s12519-009-0062-x

Background: Enzyme replacement therapy (ERT) has been increasingly used as an interim treatment in severe mucopolysaccharidosis type I (MPSI)/Hurler patients prior to hematopoietic stem cell transplantation (HSCT).

Methods: We present the outcome of a patient with MPSI/Hurler after 14 months of ERT prior to HSCT.

Results: Urinary glucosaminoglycan excretion decreased by 70% after one month of ERT. Liver volume decreased by 14% of baseline after 12 months of ERT. Pre-existing thoracolumbar kyphosis progressed to thoracolumbar dislocation with complete displacement of facets after 12 months of ERT. New development of mitral valve thickening was found by echocardiography and mild hearing loss progressed to severe sensorineural hearing loss after 13 months of ERT.

Conclusions: ERT over a period of 14 months did not prevent progression of organ manifestations in our patient. Patients should be monitored every 6 months for cardiac, skeletal and audiological involvement on ERT.

Key words: Hurler disease; laronidase;  mucopolysaccharidosis type I

World J Pediatr 2009;5(4):319-321