Mucopolysaccharidosis IVA (MPS IVA) is a rare autosomal recessive lysosomal storage disorder resulting from N-acetylgalactosamine-6-sulfatase (GALNS) deficiency that occurs in approximately 1 in 76 000 to 1 in 640 000 live births. Given that the diagnosis of MPS IVA relies heavily on the results of initial urine glycosaminoglycan (GAG) screening, cases that present with falsely normal urine GAG concentrations can delay the diagnosis and follow-up care for patients. This case study follows a patient diagnosed with MPS IVA at 9 months of age based on relation to a consanguineous 3-year-old sibling with MPS IVA and the use of direct enzyme activity analysis. Details regarding skeletal presentation and identification of genetic variants are presented along with data on follow-up urinary GAG monitoring during treatment with enzyme replacement therapy and treatment for a growth hormone disorder.
Bibliographical noteFunding Information:
SNT acknowledges financial support from the University of Minnesota Department of Laboratory Medicine and Pathology for the publication of this article.
© The Author(s) 2021.
Copyright 2021 Elsevier B.V., All rights reserved.
- enzyme replacement therapy
- growth hormone deficiency
- keratan sulfate
- Mucopolysaccharidosis IVA
- N-acetylgalactosamine-6-sulfatase (GALNS)