General Information About Fragile X Syndrome
Disease Details and Frequently Asked Questions
It is the most common cause of inherited intellectual disability, occurring because a specific protein (FMRP) necessary for brain development cannot be produced due to a genetic mutation.
It is carried on the X chromosome. Because females have two X chromosomes, the effects may be mild, but since males have only one X chromosome, if the gene is defective, the disease manifests fully and severely.
A long and narrow facial structure, large or prominent ears, flat feet, hypermobile (extremely flexible) joints, and large testicles (macroorchidism) that become prominent after puberty are typical physical features.
Intellectual disability ranging from mild to severe is observed. Patients avoid eye contact, flap their hands, or bite themselves. Due to these features, they are frequently confused with Autism Spectrum Disorder or ADHD (Attention Deficit Hyperactivity Disorder).
When a clinical suspicion arises (delayed speech, autistic symptoms), a definitive diagnosis is established by performing specific genetic blood tests that confirm the DNA expansion in the FMR1 gene.
There is no genetic cure for the disease. The main goal of treatment is to increase the individual's integration into society with intensive special education, speech/language therapy started at an early age, and medications to control hyperactivity or anxiety.
Our health library contents are prepared for informational purposes only and with scientific data available at the time of recording. For all your questions, concerns, diagnosis, or treatment regarding your health, please consult your doctor or a healthcare institution.



