FXS, or Fragile X syndrome, is a genetic condition that affects development. It is caused by a mutation in the FMR1 gene, which is located on the X chromosome. FXS is the most common inherited cause of intellectual disability, and it affects males more severely than females.
FXS can cause a range of symptoms, including intellectual disability, learning difficulties, behavioral problems, and physical features such as a large head and prominent ears. There is no cure for FXS, but there are treatments that can help to improve symptoms and quality of life.