What is Fragile X Syndrome? Intellectual Disability (ID) affects 3% of children. It results in delayed cognition development and has significant effect on functions in daily activities. An increasingly large proportion of children with ID are now found to have a genetic cause for their disability.
Fragile X Syndrome (FXS) is the most common cause of autism and will cause seizures in many patients. Novel therapeutic options are emerging with FXS.
FXS overlaps with other ID causes in terms of molecular pathway and as such, it is believed that a better understanding of it will also help to better understand other causes of ID.
Intellectual disabilities, ranging from mild to severe.
Attention deficit and hyperactivity, especially in young children
Anxiety and unstable mood
Autistic behaviours, such as hand-flapping and avoiding eye contact
Sensory integration problems, such as hypersensitivity to loud noises or bright lights
Speech delay, with expressive language more severely affected than receptive language.
Seizures (epilepsy) affect 25% of people with FXS
What are the physical characteristics of Fragile X Syndrome?† These characteristics may be hard to recognize in babies and young children, but sometimes becomes more apparent with age. Not everyone with FXS has these signs.
Long face, prominent ears, flat feet
Hyperextensible joints, especially fingers
Low muscle tone
Males may have large testes after puberty
What causes Fragile X Syndrome?† One gene shuts down: FXS is caused by a mutation in a single gene. In this case, a defect (full mutation) turns the gene off and it cannot manufacture the protein that it normally makes.
Fragile X is inherited: A mother who carries Fragile X is 50% likely to pass the mutated gene to her children, who will either be carriers or be diagnosed with Fragile X Syndrome. A father who is a carrier will pass it to all of their daughters and none of their sons. Fragile X can be passed silently through the generations before a child is born with the syndrome.
How is Fragile X Syndrome diagnosed?† Direct DNA testing, ordered by any doctor, will determine whether there is a mutation in the X chromosome. This testing is generally covered by a heath care plan, and requires a blood sample.