Title:Bone Remodeling in an Mps-1h Girl after Hematopoietic Stem Cell
Transplantation along with Enzymatic Replacement Therapy
Volume: 22
Issue: 14
Author(s): Albina Tummolo*, Giacomina Brunetti, Laura Piacente, Antonio Marzollo, Alessandra Biffi, Alberto Burlina and Maria Felicia Faienza
Affiliation:
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children Hospital, Azienda
Ospedaliero-Universitaria Consorziale, Bari, Italy
Keywords:
HSCT, ERT, mps-1h, osteoclastogenesis, rankl, glycosaminoglycan.
Abstract:
Background: Mucopolysaccharidosis-1H (Hurler syndrome, MPS-1H) is the most
severe form of a lysosomal storage disorder (LSD) caused by variants in IDUA, encoding alpha-
L-iduronidase (IDUA). MPS-1H is also associated with various degrees of skeletal defects due
to the accumulation of partially degraded glycosaminoglycans (GAGs) in the lysosomes of
connective tissue cells. The efficacy of hematopoietic stem cell transplantation (HSCT) and
enzymatic replacement therapy (ERT) on MPS-1H skeletal manifestations is still considered
unsatisfactory.
Case Presentation: We report the case of a young girl, who manifested significant changes in
bone remodeling markers and osteoclastogenesis potential after HSCT combined with ERT. She
received ERT and underwent two HSCTs. The skeletal alterations at the time of diagnosis showed
a trend toward improvement of both mobility and radiological features after HSCT. We observed
the highest levels of Receptor activator of nuclear factor-kappa-Β ligand (RANKL) and
RANK/osteoprotegerin (OPG) ratio at diagnosis and during ERT, consistently with spontaneous
osteoclastogenesis. Conversely, after the successful HSCT with ongoing ERT, the highest levels
of osteocalcin were observed and all markers of bone formation and resorption improved.
Conclusion: The combination therapy of ERT and HSCT was effective in reducing osteoclast
activity and increasing osteoblast activity, and these changes were according to the child's bone
phenotype, IDUA activity, and Glycosaminoglycan (GAG) trends. These results represent one of
the few pieces of human evidence in this context.