What is Fragile X Syndrome ?
Fragile X is the most common inherited cause of mental impairment and the most common known cause of autism, affecting approximately 1 in 4000 males and 1 in 6000 females with the full mutation worldwide. It is estimated that 1 in 259 females and 1 in 800 males are carriers of the pre-mutation.
Fragile X also includes fragile X associated tremor ataxia syndrome (FXTAS), a balance, tremor and memory condition that affects some older male carriers of the pre-mutation. Fragile X can also include problems for female carriers such as early menopause, medically referred to as premature ovarian failure (POF).
What Are the Common Symptoms of Fragile X ?
Symptoms vary from person to person and in the degree of effect and include:
- mental impairment, ranging from learning disabilities to mental retardation
- attention deficit and hyperactivity
- anxiety and unstable mood
- autistic behaviors
- long face, large ears, flat feet
- hyperextensible joints, especially fingers
- Seizures (epilepsy) affect about 25% of people with fragile X
Boys are typically more severely affected than girls. While most boys have mental retardation, only one-third to one-half of girls have significant intellectual impairment; the rest have either normal IQ or learning disabilities. Emotional and behavioral problems are common in both sexes.
About 20% of boys with fragile X meet full criteria for autism. Most boys and some girls have some symptoms of autism, but many tend to be very social and interested in other people.
What causes Fragile X Syndrome ?
In 1991, scientists discovered the gene (called FMR1) that causes Fragile X. In individuals with Fragile X Syndrome, a defect in FMR1 (a full mutation) shuts the gene down. Like a defective factory, the FMR1 gene cannot manufacture the protein that it normally makes.
Some indiviuals are carriers: they have a small defect in the FMR1 gene (called a premutation) but do not show symptoms of Fragile X.
Fragile X is inherited. Males have only one X chromosome which is inherited from the mother. They receive a Y chromosome from the father. Females inherit two X chromosomes, one from each parent. Carrier men (transmitting males) pass the premutation to all their daughters but none of their sons. Each child of a carrier woman has a 50% chance of inheriting the gene. The fragile X premutation can be passed silently down through generations in a family before a child is affected by the syndrome. A DNA blood test identifies both carriers and affected individuals.
Links to Fragile X Resources in Victoria
Fragile X Association of Victoria
The aim of the group is to provide information and support to those people whose lives have been affected by Fragile X. Services include the organising of family events, seminars, newsletter, a peer counselling service, webpage, addressing issues and concerns put to the committee by Fragile X families and to promote research, education and public awareness of the syndrome by fundraising, media coverage and other activities.
The Fragile X Alliance in Melbourne provides advice, education, therapy and medical treatments for Fragile X Syndrome. The Fragile X clinic was established in April 1998 to meet the specific needs of families.
Links to Fragile X Resources Online
Fragile X Research Foundation - FRAXA
FRAXA's mission is to accelerate progress toward effective treatments and ultimately a cure for Fragile X, by directly funding the most promising research.
FRAXA also supports families affected by Fragile X and raises awareness of this important but virtually unknown disease.
The National Fragile X Foundation aim is to unite the Fragile X community
- enrich lives through educational and emotional support,
- Promote public and professional awareness, and
- advance research toward improved treatments and a cure for Fragile X.
