Adult disease burden in patients with mucopolysaccharidosis type I H (Hurler syndrome): A comprehensive literature review with patient case analysis

Introduction: Mucopolysaccharidosis type I H (MPS IH; Hurler syndrome) is a rare autosomal recessive disease that causes deficiency of alpha-L-iduronidase - an enzyme responsible for catabolizing glycosaminoglycans (GAGs). While historically considered a pediatric disease with an overall median life expectancy of 8.7 years, advances in MPS IH treatment options have extended patient lifespans into adulthood; however, long-term progression of MPS IH currently remains minimally described. This study aims to provide a comprehensive literature review about the adult disease burden of MPS IH as validated by a medical records analysis of an adult patient with MPS IH. Methods: A comprehensive literature review was conducted to establish foundational information about the mechanism of action, clinical presentation, diagnostic complexity, treatment, and knowledge gaps of MPS IH. Medical records of a 32-year-old patient with MPS IH were analyzed, and a chronology of major clinical events was constructed to demonstrate the multi-system disease burden of MPS IH in pediatric, adolescent, and adult survivorship timelines. Results: Lysosomal GAG accumulation causes onset of musculoskeletal deformities, facial and dental variations, cardiopulmonary complications, neurocognitive manifestations, and other systematic developments in MPS IH patients - all of which progress in severity over time. The patient case analysis highlights these sequelae in addition to development of dural meningiomas, thought to have resulted from childhood total body irradiation performed before hematopoietic stem cell transplantation, that required multiple craniotomy resections and gamma knife radiosurgeries and triggered seizure activity. Conclusion: This study provides a comprehensive, literature-based, clinical narrative about the adult disease burden of MPS IH as validated by a unique patient case analysis. While childhood treatments may extend MPS IH patient life expectancy, they may not prevent progressive development of common sequelae or adult-stage neuro-oncologic developments. This study may enhance physician awareness about the multi-system adult disease burden of MPS IH, improve treatment and long-term surveillance strategies for MPS IH survivors, and support clinical counseling for families affected by MPS IH.