Long-Term Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Mucopolysaccharidosis IVA: A 10-Year Follow-Up from a Single-Center Experience in China.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potential approach for pediatric mucopolysaccharidosis IVA (MPS IVA). However, delayed diagnosis and higher transplant-related complications have limited its broader use. This study investigated treatment-related benefit and up to 10-year outcomes following HSCT in children with MPS IVA. Study Design We retrospectively analyzed 19 pediatric patients with a severe phenotype of MPS IVA who underwent HSCT between January 2015 and July 2025. N-acetylgalactosamine-6-sulfatase (GALNS) enzyme activity, height growth, and organ dysfunction (cardiac, auditory, and visual) was evaluated to analyze the benefit of HSCT. The donor sources include human leukocyte antigen (HLA)-matched sibling donor peripheral blood stem cell transplantation (MSD-PBSCT, n = 5), HLA-matched unrelated donor PBSCT (MUD-PBSCT, n = 7), and single-unit unrelated umbilical cord blood transplantation (UD-UCBT, n = 7). The overall survival rate was 94.7% (18/19), apart from 1 mortality due to pulmonary infection. All surviving patients achieved full donor engraftment and durable restoration of GALNS activity. There is no severe graft-versus-host disease (GVHD) was observed. The majority of patients exhibited no deterioration in auditory, visual, respiratory, or cardiac function. During the long-term follow-up period, our cases showed a continued linear growth post-HSCT. Here we demonstrated the data of our HSCT experience in MPS IVA with the safety and efficacy of HSCT. More data with an expanded patient cohort are imperative to delineate the capacity of HSCT to repair severe skeletal manifestations in MPS IVA.