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Symptoms

The Fragile X Association of Australia lists the following features that may be found in Fragile X syndrome:

Behavioural and emotional features
  • Anxiety and shyness
  • Attention Deficit Hyperactivity Disorder (ADHD)
  • Autistic type behaviours
  • Difficulty with eye contact
  • Tactile defensiveness
  • Repetitive speech
  • Aggression
Developmental features
  • Intellectual disability
  • Learning difficulties
  • Developmental delay
  • Speech and communication difficulties
  • Difficulty with coordination
  • Difficulty with fine and gross motor skills
Physical features
  • Physical features may be subtle or not present they can include
  • Low muscle tone and loose joints
  • Long narrow face, prominent ears (in older males)
  • High palate
  • Large testicles (in post pubescent males)
  • Mitral valve prolapse – heart murmur 

The way that Fragile X syndrome affects people varies. Girls and women, because they have two X chromosomes are usually less affected than boys and men, who have one X chromosome. A person affected by Fragile X syndrome may not show all of the signs described above. Children affected by Fragile X syndrome usually show some delay in language development apparent by age two.

People who are carriers of the pre-mutation in the FMR1 gene often have high levels of anxiety and a few children will show a milder version of the full syndrome including learning disabilities, attention deficit hyperactivity disorder (ADHD), autistic traits and other psychiatric manifestations. However, an alternative genetic cause for learning problems should always be sought in pre-mutation carriers, as the pre-mutation may not be the true cause.

About 20 per cent of women who are carriers of the pre-mutation may develop Fragile X-associated primary ovarian insufficiency (FXPOI) which causes premature ovarian failure and menopause before age 40. Others may not develop FXPOI, but may have infertility with or without regular menstrual cycles.
Men, and some women, with an FMR1 gene pre-mutation are at increased risk of developing a disorder known as Fragile X-associated tremor/ataxia syndrome (FXTAS).

The lifetime risk of developing FXTAS is much higher for male pre-mutation carriers compared to female pre-mutation carriers. Up to 40 per cent of men with the pre-mutation may develop symptoms of FXTAS after age 50 years. A much lower proportion of women with the pre-mutation will develop FXTAS. FXTAS causes slowly worsening movement problems and tremor that can sometimes be misdiagnosed as Parkinson’s disease. The main features of FXTAS are the development of problems with movement and loss of balance (ataxia) leading to falls, and tremor in the hands especially when trying to make voluntary movements. Other features may include memory loss, loss of feeling and burning sensations in the feet and behavioural changes including irritability and impulsive behaviour out of character with the person’s normal behaviour.
 


Last Review Date: March 15, 2016