Case Report Volume 14 Issue 9 - 2025

Mucopolysaccharidosis Type I: Clinical Outcomes of Late Treatment

S Hajjaji, I Merroun*, S Salimi, N El Marzouki, O Ahmito and B Slaoui

Service de Pédiatrie II, Hôpital Mère Enfants A Harouchi CHU Ibn Rochd Casablanca, Morocco

*Corresponding Author: I Merroun, Service de Pédiatrie II, Hôpital Mère Enfants A Harouchi CHU Ibn Rochd Casablanca, Morocco.
Received: July 21, 2025; Published: August 13, 2025



Mucopolysaccharidosis type I (MPS1) is a lysosomal storage disease caused by α-L-iduronidase deficiency. The therapeutic approach of the disease with recombinant human α-L-iduronidase (laronidase), with a significant improvement in patient’s quality of life in various studies.

This review evaluates clinical, paraclinical outcomes, and patients quality of life, after an average of 13.5 months of laronidase treatment in two patients, diagnosed after the age of 9 with Hurler syndrome. The outcome was satisfactory. The treatment improved the patient’s quality of life, but not curative.

 Keywords: Mucopolysaccharidosis Type I; Enzyme Replacement Therapy; Laronidase; Storage Diseases; Quality of Life

  1. M Sifuentes., et al. “A follow-up study of MPS I patients treated with laronidase enzyme replacement therapy for 6 years”. Molecular Genetics and Metabolism 2 (2007): 171‑180.
  2. BT Poll-The., et al “The eye as a window to inborn errors of metabolism”. Journal of Inherited Metabolic Disease 2‑3 (2003): 229‑244.
  3. JE Wraith. “The first 5 years of clinical experience with laronidase enzyme replacement therapy for mucopolysaccharidosis I”. Expert Opinion on Pharmacotherapy 3 (2005): 489‑506.
  4. J Muenzer and A Fisher. “Advances in the treatment of mucopolysaccharidosis type I”. New England Journal of Medicine 19 (2004): 1932‑1934.
  5. ED Kakkis., et al. “Enzyme-replacement therapy in mucopolysaccharidosis I”. New England Journal of Medicine 3 (2001): 182‑188.
  6. JE Wraith., et al. “Enzyme replacement therapy for mucopolysaccharidosis I: a randomized, double-blinded, placebo-controlled, multinational study of recombinant human alpha-L-iduronidase (laronidase)”. Journal of Pediatrics 5 (2004): 581‑588.
  7. A Tylki-Szymanska., et al. “Efficacy of recombinant human alpha-L-iduronidase (laronidase) on restricted range of motion of upper extremities in mucopolysaccharidosis type I patients”. Journal of Inherited Metabolic Disease 2 (2010): 151‑157.
  8. V Valayannopoulos and FA Wijburg. “Therapy for the mucopolysaccharidoses”. Rheumatology (Oxford) 5 (2011): 49-59.
  9. ED Kakkis., et al. “Long-term and high-dose trials of enzyme replacement therapy in the canine model of mucopolysaccharidosis I”. Biochemistry and Molecular Medicine 2 (1996): 156‑167.
  10. JM Resnick., et al. “Pathology of the liver in mucopolysaccharidosis: light and electron microscopic assessment before and after bone marrow transplantation”. Bone Marrow Transplant3 (1992): 273‑280.

I Merroun., et al. “Mucopolysaccharidosis Type I: Clinical Outcomes of Late Treatment”. EC Paediatrics  14.9 (2025): 01-05.