Kleefstra Syndrome

Also known as

  • KS 9q34.3 deletion syndrome 9qSTDS (subtelomeric deletion syndrome)

KS is a rare genetic disorder characterised by intellectual disability, often accompanied by a spectrum of complex physical and clinical features.

Condition details

Developmental delay, Learning difficulty or disability, Low muscle tone (babies and children feel floppy), Severely limited or absent speech.

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Photos of affected individuals

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  • No baby imageBaby
  • No toddler imageToddler
  • No child 4-10 imageChild 4-10
  • No child 10-18 imageChild 10-18
  • No adult imageAdult

Typical age range of first manifestation

  • Can manifest in Baby
  • Does not manifest in Toddler
  • Does not manifest in Child 4-10
  • Does not manifest in Child 10-18
  • Does not manifest in Adult


Affected genes identified to date

  • EHMT1

Inheritance patterns

Is Autosomal dominant

Most cases are de novo (due to a new spontaneous genetic change). Each child of someone with KS has a one in two chance of inheriting the condition.

Are carriers affected?

How many are affected?


Support groups and organisations

Facebook www.facebook.com/Kleefstrasyndrome.org/

Known experts

No experts found

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