What is Kleefstra Syndrome

Kleefstra syndrome is a rare genetic condition in which a tiny piece is missing from near the end of one of the body’s 46 chromosomes. The missing piece includes a gene called EHMT1. Its absence is believed to cause the major symptoms of the syndrome. The syndrome was officially recognised as Kleefstra syndrome in April 2010 but you may still see it referred to as any of the following:
  • 9q34.3 deletion
This was the most common name before Kleefstra Syndrome was recognised, and in fact our original website address was www.9q34.org In April 2010 OMIM recognised the term "Kleefstra syndrome" and in May 2010 our website adopted the new name.  
  • 9qSTDS
Short for 9q Subtelomere Deletion Syndrome - It was suggested by a specialist in the field that this become the uniformed name. Some parents disliked this however, due to other meanings of the term STD.
Short for Craniofacial characteristics, Hypotonia, Obesity, Microcephaly, Speech problems.  It was suggested to be the uniformed name by one of the specialists looking at the condition.
Other variations are:   
  • 9q34.3 microdeletion
  • 9q34.3 terminal deletion syndrome

Information reproduced with permission, from Unique's Kleefstra syndrome leaflet.

Additional information