June 03, 2026 —
IDefine – The Kleefstra Syndrome Foundation has announced a research collaboration with UT Southwestern Medical Center to advance development of a potential gene therapy for Kleefstra syndrome, a rare neurodevelopmental disorder caused by changes or loss of the EHMT1 gene.
The two-year preclinical research program will be led by Steven Gray, PhD, professor at UT Southwestern and director of the UTSW Gene Therapy Program. The effort will evaluate the feasibility and safety of EHMT1 gene replacement therapy using next-generation gene delivery technology designed to target the central nervous system.
Kleefstra syndrome is caused by disruption of EHMT1, a gene that plays an important role in brain development and function. The condition can present with a wide range of symptoms, including intellectual disability, speech impairment, low muscle tone, seizures, and behavioral challenges. Disease severity can vary significantly, from mild to profound. There are currently no approved treatments for Kleefstra syndrome.
The collaboration reflects growing interest in applying CNS-directed gene therapy to complex neurodevelopmental disorders. By replacing or restoring EHMT1 expression, the research program aims to explore whether gene therapy could address the underlying genetic cause of the disease. At the same time, the investigators will focus on key translational questions, including delivery to the CNS, safety, and appropriate regulation of gene expression.
Under the agreement, IDefine will provide approximately $310,000 in funding to support the preclinical program, which is expected to continue through April 2028. The partnership brings together IDefine’s patient-driven mission to accelerate treatment development with UT Southwestern’s expertise in gene therapy research and CNS delivery.
Founded in 2020 by parents of children diagnosed with Kleefstra syndrome, IDefine has become a leading nonprofit patient advocacy organization dedicated to supporting affected families, funding research, and building collaborations with clinicians, researchers, and industry partners.
While the program remains at an early preclinical stage, the collaboration marks an important step toward evaluating a potential first disease-modifying therapy for Kleefstra syndrome. If successful, the research could help lay the foundation for future translational development of EHMT1 gene replacement strategies for patients and families affected by this rare disorder.
