Fragile X Syndrome is a genetic defect. It is the absence of a functional fragile X gene (FMR1) that
shuts down the production of a special protein in the brain needed for normal cognitive
development. Without this protein, children with the syndrome will never learn normally, despite
hours of therapy and rehabilitation. Fragile X syndrome is a hereditary disorder which causes a
wide range of mental impairment, from mild learning disabilities to severe mental retardation.
Fragile X syndrome is the leading hereditary cause of developmental disabilities. In addition to
mental impairment, fragile X syndrome is associated with a number of physical and behavioral
In 1991, scientist discovered the gene called (FMR1) which causes Fragile X. Fragile X Syndrome, a
defect in which the absence of a functional fragile X gene (FMR1) shuts off production of a special
protein in the brain needed for normal cognitive development. Cognitive development is defined as
thinking, problem solving, concept understanding, information processing and overall intelligence.
Without this protein, children with the syndrome will never learn normally, despite hours of therapy
The exact frequency of Fragile X is unknown. The full mutation appears in approximately 1 in 2000
males and 1 in 4000 to 6000 females. The carrier, usually a transmitting male, passes the pre-
mutation gene (FMR1) to all their daughters, but none of their sons. Females are also be affected,
approximately 30% of females with full mutations are mentally retarded, and their level of retardation
is, on average, less severe than that seen in males. Approximately one third of female carriers of
full mutation gene (FMR1) will have mild to moderate mental disabilities. Each child of a carrier
woman has a 50% chance of inheriting the gene. The Fragile X pre-mutation gene can be passed
silently down through generations in a family before the syndrome affects one child. A DNA blood
test identifies both carriers and affected individuals.
Some of these children may have certain facial features which include everted ears and elongated
faces. Behaviors may include hyperactivity and autistic characteristics may be present. Such as
chewing on skin, clothing, or objects, which may be connected to sensory processing problems and
anxiety. Sensory processing problems may manifest themselves as tactile defensiveness, such as
oral motor defensiveness, sensitivity to sound or light, and poor eye contact. About 90% of boys
with fragile X syndrome are reported to have some type of sensory defensiveness. Tantrums may
be a result of anxiety and a feeling of being overwhelmed. Crowds and new situations may cause
boys to whine, cry, or misbehave, in attempts to get out of the overwhelming settings.
Like many developmental disorders such as autism, Fragile X syndrome include all ranges of
impairment from profound mental retardation (MR) to mild learning difficulties, as well as
developmental delays, autistic-like behavior, hyperactivity and other behavior disturbances.
The poor eye contact and difficulty sustaining a conversation cause many social weaknesses.
Perseverative speech and self-talk may be symptoms of anxiety.
Some behaviors that overlap with the diagnosis of autism are often reported. The majority of
children with fragile X syndrome do not have all the characteristics of autism, but about 15% to 33%
are diagnosed as autistic. More often, children have "autistic-like" features, such as poor eye
contact, hand flapping, and poor social skills.
Girls with the full mutation of the fragile X gene appear to have some specific areas of concern in
the area of behavioral and emotional difficulties. Shyness, anxiety, depression and difficulties with
social contacts are most often mentioned as characteristics of girls with fragile X.
Some behaviors include:
• Mental retardation
• Short attention span
• Tactile defensive / touch sensitivity
• Poor eye contact
• Repetitive Speech
• Double Jointed
• Large or prominent ears
• Large testicles
• Simian crease - a single horizontal crease on the palm instead of the usual two
|What is the Fragile X gene (FMR1)?
The FMR-1 gene is located on the X chromosome. This gene is responsible for instructing the cell to
make FMRP, a protein assumed to be essential for normal brain functioning.
Fragile X is the leading form of autism: 90 % of Fragile X patients have autistic features, 50% of
pre-school Fragile X children meet autism diagnostic criteria, and 6% of all autistic individuals turn
out to have fragile X. Fragile X also gives rise to anxiety disorders, attention deficit hyperactivity
disorder, psychosis, obsessive-compulsive disorder, and many other problems.
There is currently no cure for Fragile X Syndrome, although appropriate education and medications
can help maximize the learning potential of each child. However, most boys and many girls remain
significantly affected throughout their lives. The need for treatment and special education are
significant. The need for research aimed at treatment is urgent.
Recent significant progress has been made in understanding mechanisms and developing potential
treatments for inherited diseases that are caused by a single gene, such as Fragile X.
Current medical research focuses on: Gene Therapy - studying the gene that causes Fragile X in
order to determine whether a healthy gene may be inserted into the cells of affected individuals,
thereby replacing the mutated, ineffective gene.
Protein Replacement Therapy - studying the protein product that is lacking due to the mutation, in
hopes that the protein may be supplemented from an external source.
Psychopharmacology - treating the symptoms of the disorder with medications.
Many researchers believe that medical treatment, when it becomes available, will be able to help
Fragile X individuals of all ages. Experts think that the missing FMR protein has a regulatory function
in the brain, rather than a structural function, and that this protein is needed throughout a person's