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Fragile X syndrome


ICD-10: Q99.2

ORPHA: 908

General information

Estimated occurrence
1:5,000 boys and 1:4,000 girls have the genetic mutation that causes Fragile X syndrome. All boys, but only 20% of the girls, who have the mutation also have the symptoms.
An unstable DNA segment on the long arm of the X chromosome. Girls almost always have less severe symptoms, since females have two X chromosomes.
General symptoms
Delayed psychomotor development. Varying degrees of intellectual disability. Many of these children have concentration problems and poor endurance. There may be some autism spectrum or autism-like features, and there is an increased frequency of epilepsy. There may be a cardiac defect, mitrialis valve prolapse, usually unproblematic.

Orofacial/odontological symptoms

Characteristic facial features are associated with the diagnosis. These features are less pronounced in children. Many have malocclusions. Speech, language and communication difficulties are frequent, as are eating and drooling problems. Speech is often rapid. Mouth hypersensitivity may occur, and be problematic in terms, for instance, of feeding and tooth brushing.

Advice on follow-up and treatment

  • Early contact with dental services for intensified prophylactic and oral hygiene information is essential.
  • Regular check-ups of dental and jaw development. Orthodontist should be consulted when needed.
  • Orofacial therapy and oral motor skills training in cases of difficulties with eating, speech or drooling.
  • Speech, language and communication training are often required.
  • When treating medically compromised patients always contact their doctors for medical advice.


Updated: 2019-11-12 14:45