Growth Failure in STAT3 Gain-of-Function Syndrome Persists After Hematopoietic Stem Cell Transplantation

STAT3 gain-of-function syndrome (STAT3 GOF) is an inborn error of immunity (IEI) characterized by severe immune dysregulation and multi-organ involvement. This report describes the long-term growth outcomes of two patients with STAT3 GOF following hematopoietic stem cell transplantation (HSCT). Pre-transplant, both patients exhibited significant growth failure due to organ complications and potential growth hormone (GH) insensitivity. While HSCT resolved immune-related complications, it did not improve growth trajectories, suggesting an intrinsic growth defect driven by STAT3 hyperactivity and reduced STAT5 signaling. These findings emphasize the need for post-transplant multidisciplinary care and further studies to explore targeted interventions for growth impairments in STAT3 GOF.