Does anyone know what Fragile-X syndrome is?

Question

It is a specific learning disability, any clues

Answer 1

Fragile X syndrome is the most commonly inherited form of mental retardation. Although it is thought to be an X-linked recessive trait with variable expression and incomplete penetrance, 30% of all carrier women are also affected. The syndrome is called “fragile-X” because there exists a fragile site or gap at the end of the long arm of the X-chromosome in lymphocytes of affected patients when grown in a folate deficient medium.

Carrier females typically have a 30 to 40% chance of giving birth to a retarded male and a 15 to 20% chance of having a retarded female. Further, there frequently exists a maternal family history for a relative with mental retardation or developmental and learning disabilities. Most studies have dealt with recognition of this syndrome in older children and young adults, but many of the physical features, behavioral characteristics, and family history features are apparent earlier.

Prominent parental concerns that might bring such a child to a pediatrician’s attention include: Developmental delay, speech delay, short attention span or hyperactivity, mouthing of objects persisting at an age beyond expected, difficulty in disciplining the child, frequent temper tantrums, autistic-like behaviors such as rocking, talking to oneself, spinning, unusual hand movements, difficulty with transitions, preference for being alone, echolalia, poor eye contact; poor motor coordination; history of vomiting, spitting up or colic during infancy; history of frequent otitis media; self-abusive behavior; hand flapping; drooling persisting beyond expected; hypotonia; increase fighting with others; pica; hand/thumb sucking.

While older children (8-12 years) are more likely to display the classic physical features of fragile X syndrome (long face with a prominent jaw, large prominent ears, and post-pubertal macroorchidism, patients as young as 2 or 3 years have been noted to exhibit the following physical findings: Long and/or wide and/or protruding ears; prominent jaw or long face; high arched palate; flattened nasal bridge; microcephaly or relative macrocephaly; apparent hypertelorism; epicanthal folds; simian creases of palms, vertical creases of soles; long philtrum; hemangioma; hyperextensible joints; antimongoloidal slant; clinical impression of macroorchidism, prominent forehead.

It is not feasible or wise to recommend chromosomal studies on all children with developmental, learning, and behavioral disabilities. But these problems (particularly speech delay, unusual behaviors, and developmental delay) taken in context with a maternal family history of mental retardation or developmental disabilities and the physical finding of long, wide, or protuding ears, a long face, flat nasal bridge, and a high arched palate probably warrant a search for the fragile X chromosome. A new method of identifying carriers of these mutations by direct DNA analysis has recently been described.

Answer 2

Check this out:

The National Fragile X FoundationFeatures information about the disease, its treatment, and inheritance.
www.fragilex.org/ - 5k - Cached - Similar pages

Answer 3

There is a website i found so there you can find the anwers you want to know.

Answer 4

Fragile X is the most common inherited cause of mental impairment and the most common known cause of autism.
What Are the Common Symptoms of Fragile X?

Features usually 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.
In 1991, scientists discovered the gene (called FMR1 for "Fragile X Mental Retardation - 1") that causes fragile X. In people with Fragile X, a defect in FMR1 (a "full mutation") shuts the gene down. Like a defective factory, FMR1 cannot manufacture the protein that it normally makes.

Other individuals are carriers: they have a small defect in FMR1 (called a "premutation") but do not show symptoms.

Fragile X is inherited. Carrier men 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.



The Fragile X Gene

The FMR1 gene is located on the long arm of the X chromosome. Within this gene lies a region of DNA which varies in length from one person to another. Ordinarily, this stretch of DNA falls within a range of length that would be considered "normal".

In some people, however, this stretch of DNA is somewhat longer; this gene change is called a "premutation". Although a person who carries the premutation does not typically have symptoms of Fragile X, the stretch of DNA is prone to further expansion when it is passed from a woman to her children. When the stretch of DNA expands beyond a certain length, the gene is switched off and does not produce the protein that it is normally makes. This gene change is called a "full mutation".



A male who inherits a full mutation exhibits Fragile X syndrome because his only X chromosome contains the mutated gene. A female may not be as severely affected because each cell of her body needs to use only one of its two X chromosomes and randomly inactivates the other.



How is Fragile X inherited?

Each cell in the body contains forty-six (twenty-three pairs of) chromosomes. These chromosomes consist of genetic material (DNA) necessary for the production of proteins which lead to growth, development and physical/intellectual characteristics. The first twenty-two pairs of chromosomes are the same in males and females. The remaining two chromosomes, X and Y, determine whether a person is male or female.

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.



How common is Fragile X?

Fragile X syndrome is the most common inherited cause of mental impairment and the most common known cause of autism. Fragile X affects 1 in 4000 males and 1 in 6000 females of all races and ethnic groups (source Centers for Disease Control (CDC) ). About 1 in 259 women carry fragile X and could pass it to their children. About 1 in 800 men carry fragile X; their daughters will also be carriers.

Large-scale population studies of fragile X still need to be done, but it is clear that this is one of the most common genetic diseases in humans. Most people with fragile X are not yet correctly diagnosed.

A DNA test for Fragile X was developed in 1992. This blood test is accurate and can detect both carriers and fully-affected individuals. It can be ordered by any physician; the blood sample is then sent to a lab that offers the test. It usually takes several weeks to get the results.

Because the symptoms of Fragile X can be quite subtle, especially in young children, and because it is so frequent in the general population, many medical specialists recommend that testing for Fragile X be considered for any individual with otherwise unexplained developmental delay or mental retardation.

Most major medical centers in the United States offer the Fragile X test. It costs about $200 but may be covered by health insurance. For more information about testing, talk to your doctor or genetic counsellor.

April 2005: Standard Reference Material from the National Institute of Standards and Technology (NIST) was released to help clinical genetics labs improve the accuracy of Fragile X diagnostic tests.



Are there any Treatments?

There is currently no cure for Fragile X, although appropriate education and medications can help maximize the potential of each child. However, most boys and many girls remain significantly affected throughout their lives. The cost to society for treatment, special education, and lost income is staggering. The need for research aimed at treatment is urgent.

FRAXA-funded research has already achieved significant breakthroughs in understanding Fragile X. We now know that the FMR protein's normal role is to help shape the connections between neurons (brain cells) that underlie learning and memory, and we are beginning to understand how the lack of the protein causes Fragile X syndrome. Because absence of the FMR protein seems to delay the development of neurons, rather than damage or destroy them, it appears likely that treatments now being investigated can potentially benefit all individuals with Fragile X, regardless of age.

Currently we are supporting several avenues of research, including gene therapy, protein replacement, and pharmacology. For more about current research projects and FRAXA strategy

Answer 5

www.fraxa.org

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