Early Stem Cell Transplantation May Improve Survival in Rare Inherited Bone Marrow Disorder

More than 90% of affected children survive beyond age 20, but fewer than 30% live beyond age 50. The major clinical threat is development of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), or bone marrow failure. A new study shows that earlier hematopoietic cell transplantation may improve survival when high-risk features appear.

Cincinnati Children’s Hospital Medical Center and the International SDS Research Consortium evaluated outcomes in the largest known collection of SDS data. The analysis included 847 cases involving patients from infancy to beyond age 50. SDS most often occurs when both parents pass on a mutated form of the SBDS gene. The condition can affect the pancreas, skeletal system, liver, and central nervous system, but its most serious complications involve the bone marrow.

The study indicates that hematopoietic cell transplantation (HCT) may be beneficial before patients develop advanced malignant disease. The high-risk features identified include clones of mutated bone marrow cells and signs of progressive dysplasia. Current practice often delays HCT until patients develop MDS or AML. The findings suggest that this approach may miss an earlier therapeutic window.

The cumulative risk of MDS, AML, and bone marrow failure was nearly 78% by age 50, although the incidence of potentially lethal malignancies was as low as 2% among 5-year-olds. Among 24 high-risk patients who underwent HCT, nearly 82% were alive two years later. Survival was lower among patients who already had MDS, at 55%, and among those with AML, at 36%. The study was published in The New England Journal of Medicine on September 23, 2026.

Wider use of genetic screening may help identify more children with SDS and support earlier monitoring for high-risk biomarkers. The source text also notes that stem cell transplants can be expensive and carry risks of complications, which may limit access in low-resource settings. Additional research is needed to define the ideal age and risk factors for HCT and to assess whether alternative therapies can be developed.

“For patients with this rare condition, waiting until malignancies are diagnosed may be too late,” said Kasiani Myers, MD, of the Division of Bone Marrow Transplantation and Immune Deficiency at Cincinnati Children’s.

“These data support surveillance and early HCT for patients who develop high-risk features to preempt malignancy,” stated the co-authors.

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