Fragile X Syndrome - An Introduction

What is Fragile X Syndrome?

Fragile X syndrome is the most common cause of inherited intellectual disability (mental retardation). It is a disabling genetic condition which results in serious problems with learning and behaviour. Fragile X is found worldwide, in all ethnic groups and throughout society. Every week in Australia one child is born who is fully affected and twelve children are born who are carriers.*

All males who carry the mutation will pass it to their daughters. And females have a 50% chance of passing the condition to their children.

There is currently no cure for Fragile X but special therapies, methods of teaching and medication all provide real benefit to people with the syndrome and help them perform the best they can.

*(Average based on International statistics indicate that 1 in 3600 males and 1 in 4000-6000 females are affected, 1 in 260 females and 1 in 800 males are carriers)

Intellectual Characteristics

Developmental delays are the most significant characteristic of those with fragile X. The range of learning problems is wide. Some are affected in fairly small ways, while at the other end of the scale, especially with males, there can be severe intellectual disabilities. Most affected males fall somewhere in the middle. Learning disabilities are often accompanied by delays in speech and communication skills. There can also be delays in both gross motor (such as sitting and walking) and fine motor (such as holding a pencil) skills. In general, females are not as delayed as males.

Physical characteristics

People affected by fragile X syndrome are generally healthy. They do not suffer from major medical problems because of the syndrome and have a normal life expectancy.

People with fragile X syndrome do not look very different from other people.

Some, but not all, people with fragile X have some or all of the following features:

• a long face
• ears which stick out from the head
• connective tissue weakness, leading to floppy muscle tone and flat feet
• extremely flexible joints
• many ear infections in children
• a squint as well as long or short sightedness
• larger testicles

Behavioural Characteristics

People with fragile X can behave differently from other people. Both males and females tend to have:

• delayed speech
• anxiety
• trouble coping with sensory stimuli
• autistic-like features such as hand flapping and avoiding eye contact
• saying or doing the same thing over and over
• Attention Deficit Disorder (ADD) or Attention Deficit Hyperactivity Disorder (ADHD)
• poor concentration
• dislike of change in routine
• poor social skills
• tantrums and emotional outbursts

Education

Because speech and language are very often delayed and because of their poor concentration, children with fragile X may seem hard to educate. However, the child may have more ability than he or she can demonstrate. There are good points as well as bad points that affect the education of children with fragile X.

Strengths may include:

• good copying skills
• excellent long-term memories
• good senses of humour
• often good vocabulary and reading skills

Genetics

Fragile X is a genetic syndrome carried on the X chromosome. Females have two X chromosomes (one from each parent) and males have one X chromosome (from the mother) and one Y chromosome (from the father). If the X chromosome in males is affected they will have fragile X syndrome. Females will have a second (non-affected) X chromosome, which acts like a back up, and they can be less affected.

Testing

There are now very good tests to determine whether a person has fragile X, which consist of DNA studies of a blood sample. DNA testing should be carried out if a person has an intellectual disability of unknown cause, is developmentally delayed or has characteristics like autism. If a family member is known to have fragile X, other members should be tested. Women thinking about getting pregnant should be tested if any of the usual signs of fragile X are present in any family members. A pregnant woman can have her foetus tested.

Accurate DNA testing for fragile x is available through Genetic Services which have clinics throughout hospitals and Community Health Services in Australia. Alternatively, you can see your local doctor or paediatrician to arrange the testing (some private professionals charge). The test is a bloodtest called “DNA Studies for fragile x syndrome” and is covered by Medicare with a referral when testing through a geneticist or paediatrician.

To find a Genetic Service please go to www.genetics.com.au/services/counsel.htm. If you are in NSW, please go the Fragile X Service at www.hunter.health.nsw.gov.au/genetics/fragilex.htm

Counselling

Genetic counselling should always be made available if there has been a positive result from a DNA test for fragile X. Counselling may help parents and families overcome the worry and distress of a positive test. Local fragile X associations can assist by providing support by families in a similar situation and in referring families to professional sources of counselling.

Further Help

Specialist therapies, targeted education and medication can all improve the quality of life for those affected with fragile X. The Fragile X Association of Australia provides family support and information.  Please go to our contact us page for contact details.