X-Linked Creatine Deficiency
X-linked creatine deficiency primarily affects development of the brain and nervous system. Symptoms can begin at any age, but usually begin in early childhood. These symptoms can include mild to severe intellectual disability, delayed speech development, behavioral problems, and seizures. The intellectual disability may get worse over time. X-linked creatine deficiency is caused by a SLC6A8 gene that is not working correctly. It is inherited in an X-linked pattern. Diagnosis is based on screening tests, clinical exam, and genetic testing. Treatment is focused on managing the symptoms.