Fragile X syndrome is an inherited condition caused by a defect on the X chromosome that results in intellectual disabilities ranging from mild to severe. It is characterized by symptoms such as intellectual disabilities, attention issues, anxiety, autism-like behaviors, sensory issues, speech delays, seizures, and in males large testes after puberty. The condition is caused by a gene called FMR1 that is normally switched off in people with Fragile X syndrome, preventing normal brain development. While there is no cure, treatments can help minimize symptoms and include genetics, education, medications, and therapy.