Fragile X Syndrome

Fragile X Syndrome (FXS) is a genetic syndrome that can cause a variety of developmental and intellectual disabilities. The disabilities can range from mild to severe and can also affect emotional and behavioral features.

It's an inherited condition meaning it's passed down from parents to children. Parents can carry the Fragile X gene even if they don't have the condition themselves. Children can be born with this mutated gene even if the parents aren't carriers. If the parents are carriers or have Fragile X, the changes in the gene can be more serious when passed to the child, according to medical experts.

FXS is also called Martin-Bell Syndrome. In South American countries the condition is sometimes referred to as Escalante's Syndrome

The Science Behind the Syndrome

FXS is caused when a change occurs in a single gene called the Fragile X Mental Retardation 1 (FMR1) gene. The change occurs when a certain gene sequence, the expansion of a single trinucleotide gene sequence (CGG) on the X chromosome, doesn't happen as it should on the X chromosome. This causes the FMR1 protein coding to fail. This protein is essential for normal neural development.

The FMR1 gene can vary is severity of mutation. A small change in the gene is called a permutation and could mean the individual won't show any signs of Fragile X. A full mutation means that there will be symptoms of Fragile X. There are also gray or intermediate zones with this gene mutation causing the person with the mutation to show some symptoms and signs of Fragile X.

Signs and Symptoms of Fragile X

Not every person with Fragile X will have the same symptoms and signs so it's difficult to create a generalized list of symptoms. Severity can vary as well with boys tending to have more severe symptoms than girls.

Those with Fragile X tend to have prominent physical characteristics of the condition. These include overall low muscle tone, large or protruding ears, an elongated face, narrow jaw line, unusually loose and flexible joints and flat feet. Men often have larger testes.

Social, emotional and intellectual development may also be affected. Many people with the syndrome have intellectual challenges from mild learning disabilities to severe learning difficulties. They tend to get afraid or anxious in new situations which could cause aggression (more often in boys) or extreme shyness (more often in girls). Boys tend to have significant speech and language problems including difficulty speaking, stuttering and understanding non-verbal body clues or voice tone.

Some children with Fragile X have heightened senses and may be extremely sensitive to loud noises and bright lights. They may prefer not to be touched and may not meet eye contact with people. Some children with Fragile X cannot handle the noise and busyness of large crowds and may react with tantrums.

Fragile X and Autism

Some of the symptoms and signs of Fragile X are similar to autism. The two conditions are different but there is a connection. Fragile X Syndrome can cause autism or an Autism Spectrum Disorder (ASD). Research has shown that FXS gene mutation is the cause of autism for between two to six percent of children with the condition. About one-third of children diagnosed with FXS have ASD or autism. It's possible for a child to have Fragile X but not autism.

Is There a Cure?

Like autism, there is no cure for Fragile X. However, there are a variety of treatments available to help an individual reduce or eliminate many of the problems associated with FXS. Early intervention is ideal. A child's brain is still developing and early intervention can help the brain develop to its full potential. But even if early intervention wasn't an option, it's never too late to benefit from treatment. A well-rounded treatment plan includes physical therapy, behavioral therapy and appropriate education.