People with fragile X syndrome have intellectual disability, behavioral and learning disabilities, as well as certain physical characteristics. This disease is the most common inherited cause of intellectual disability and also the most common known genetic cause of autism. You can find more information below.
What is fragile X syndrome?
fragile X syndrome ; It is a genetic disease that causes a range of developmental and mental problems, including learning disabilities and cognitive impairment . Men are more affected by this disease than women.
Affected individuals usually have delayed speech and language development up to 2 years of age. Most men with fragile X syndrome have mild or moderate intellectual disability, while approximately one-third of women affected by the syndrome are intellectually disabled.
Children with fragile X syndrome may have impulsive actions and hyperactive behaviors. They may have attention deficit and hyperactive disorder , which includes the ability to pay attention and difficulty focusing on certain tasks .
About one-third of individuals with fragile X syndrome have features of an autism spectrum disorder that affects communication and social interaction . Seizures occur in about 15 percent of men, while this is about 5 percent of women.
Most men and about half of women with fragile X syndrome have characteristic physical features that become more pronounced with age. Among these features; a long and narrow face, large ears, prominent chin and forehead, unusually flexible fingers, flat feet, and males have large testicles after puberty.
Is it hereditary?
This syndrome is inherited with an X-linked dominant inheritance. The condition is considered X-linked if the mutated gene that causes the disease is located on the X chromosome, one of the two sex chromosomes. Heredity is dominant if one copy of the altered gene in each cell is sufficient to cause the syndrome. In most cases, men have more severe symptoms than women. A striking feature of X-linked inheritance is that fathers cannot pass on X-linked traits to their sons.
Who is it seen in?
Fragile X syndrome affects about 1 in 4,000 men and 1 in 6,000 to 8,000 women; that is, it affects about twice as many men as women. This syndrome can be seen all over the world.
Causes of fragile X syndrome
Fragile X syndrome is caused by a mutation in the FMR1 gene that prevents the body from producing an important protein called FMRP. This protein helps create and maintain connections between brain cells and the nervous system. When the FMRP protein is missing, signals from the brain can be misdirected. This causes the developmental problems and learning difficulties found in fragile X syndrome.
The FMR1 gene is located on the X chromosome, meaning women with two X chromosomes have two copies of the FMR1 gene and men have only one copy of the FMR1 gene since they carry only one X chromosome. This is why boys often have more severe symptoms than girls. If women have only one mutated FMR1 gene on the X chromosome, the other intact FMR1 gene reduces the activity of the mutated gene. Therefore, fewer symptoms related to the syndrome occur.
What are the symptoms of fragile X syndrome?
Both men and women with fragile X syndrome may have certain behavioral and mental characteristics, but girls usually have milder symptoms.
Children with fragile X syndrome may experience the following symptoms:
- delayed speech
- delayed motor skills
- Repetitive and unclear speech (especially in males)
- Autistic behaviors such as poor eye contact, hand biting, clapping, sensitivity to noise and crowds
- learning difficulties
- anxiety disorder
- Hyperactivity and short attention spans (especially in males)
- Shyness (often seen in girls)
Some children with fragile X syndrome have the following physical characteristics that may become more evident after puberty:
- big ears
- a long and narrow face
- flat feet
- Large testicles in men
- Very flexible joints
It is important to see a doctor for a definitive diagnosis, as the symptoms of fragile X syndrome are similar to or can be confused with symptoms of other conditions such as autism and Prader-Willi syndrome .
How is fragile X syndrome diagnosed?
Doctors often use a blood sample to diagnose Fragile X. The doctor will take a blood sample and send it to the lab to determine which form of the FMR1 gene is present.
Prenatal tests (during pregnancy)
Pregnant women with a premutation or full mutation of FMR1 can pass the mutated gene to their children. Prenatal testing allows doctors to detect the mutated gene in the developing fetus. This important information helps families and their doctors prepare for Fragile X syndrome and intervene as early as possible.
Possible types of prenatal testing include:
- Amniocentesis: The doctor takes a sample of amniotic fluid (the protective fluid in which the baby is) to be tested for the FMR1 mutation.
- Chorionic villus sampling: The doctor takes a sample of cells from the placenta, which is then tested for the FMR1 mutation.
Because prenatal testing does involve some risks to the mother and fetus, if you or a family member is considering prenatal testing for Fragile X syndrome, you should talk to your doctor about all the risks and benefits.
Prenatal testing is not very common, and many parents do not know they carry the mutation. For this reason, parents often start noticing symptoms in their children when they are infants or toddlers. The mean diagnosis period is 36 months for boys and 42 months for girls.
Diagnosis of the syndrome in children
Many parents first notice signs of delayed development in their babies or toddlers. These symptoms may include delays in speech and language skills, social and emotional difficulties, and sensitivity to certain feelings. Children may also be delayed or have problems with motor skills such as learning to walk.
The doctor may perform developmental screening to identify the causes of delays in a child. If a healthcare provider suspects that a child has Fragile X syndrome, they may refer them to a clinic and geneticist whose parents can perform genetic testing for Fragile X syndrome.
Fragile X syndrome treatment
There are many treatments that can improve the lives of individuals affected by fragile X syndrome and their families. These include special education, speech, vocational and sensory integration training (it is a neurological process that allows the individual to process the information perceived by his sensory organs) and behavior modification programs. With educational efforts, therapy, and support, all individuals with fragile X syndrome can make progress. Other treatment may depend on the specific symptoms of an affected individual. Genetic counseling is recommended for affected individuals and their families.
There are many clinics in the world dealing with Fragile X syndrome. These clinics specialize in treatments, therapies, and support for individuals with fragile X syndrome and guide parents in medication choices to address specific symptoms. New drugs are likely to become available to treat the affected individual, and specialist clinics can assist parents with up-to-date information.
Fragile X syndrome is a genetic condition that can cause mild to severe mental and developmental disabilities that can hinder a person’s ability to live independently.
Fragile X syndrome has no known targeted therapy and is a lifelong condition. Doctors and some disease-related communities can help support people with fragile X syndrome.