Synonyms: 9q subtelomeric deletion syndrome | 9qSTDS | Kleefstra syndrome due to 9q subtelomeric deletion | Kleefstra syndrome due to del(9)(q34) | Kleefstra syndrome due to monosomy 9q34
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version April 2026
Newly diagnosed with
Kleefstra syndrome due to 9q34 microdeletion?
Our RARE Concierge Services Guides are available to assist you by providing information, resources and connections as you navigate your rare disease journey.
Advocacy Organizations
Genetic Epilepsy Team Australia
Collaboration of research and care
IDefine
IDefine is committed to identifying life-changing treatments & cures for those with Kleefstra Syndrome and other Intellectual Disabilities, building community and resources for families.
KMT2C Foundation
KMT2C Foundation was established in 2025 as a nonprofit organization, and is incorporated in Texas, USA. We stand by our three pillars: creation of a virtual community and respite for patients and their advocates, sponsorship and collaboration for research efforts, and bridging the connection between health care professionals and molecular researchers.
PPP2CA Pathways
PPP2CA Pathways connects families, shares strength, and supports the research community in the search for answers to Houge-Janssens Syndrome type 3.
Rare Chromosome Disorder Support Group – Unique
Through sharing knowledge and lived experience, Unique helps families and professionals navigate the world of chromosome and gene disorders
Rare Epilepsy Network (REN)
Improving outcomes of people with rare epilepsies through an innovative collaborative infrastructure that drives urgent, patient-centered research, educaiton and advocacy.
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Clinical Trials
For a list of clinical trials in this disease area, please click here.