Patient case (clinical description): A 15-year-old boy with mild intellectual disability is brought to the office by his parents for a routine physical examination.  The boy is going to a school for students with learning disabilities.  The patient was adopted, and his immunizations are up to date.  Review of the patient's medical records is notable for cytogenetic studies that showed a small gap near the tip of the long arm of the X chromosome, which is consistent with fragile X syndrome, an X-linked disorder. The defect is an unstable expansion of trinucleotide repeats (CGG) in the fragile X mental retardation 1 (FMR1) gene, located on the long arm of the X chromosome. He is not using any medications and vital signs are within normal levels. His blood chemistry analysis as bellow:
Blood Chemistry Value      Normal Range     Patient Value
Glucose                    90-120 mg/dl     95 mg/dl
BUN (Blood Urea Nitrogen)  7-24 mg/dl       10 mg/dl
Creatinine                 0.7-1.4 mg/dl    0.8 mg/dl
Calcium                    8.5-10.5 mg/dl   9 mg/dl
Sodium                     134-143 mEq/L    135 mEq/L
Potassium                  3.5-4.5 mEq/L    3.7 mEq/L
Chloride                   95-108 mEq/L     98 mEq/L
CO2                        20-30 mEq/L      25 mEq/L
Blood pH                   7.38-7.42        7. 39

Patient's own account: My husband and I brought our 15-year-old son to the clinic for his routine exam. My son is going to school for special needs students. We adopted him a few years ago. His vaccinations are up to date. He already passed some chromosome testing and they found that he has a fragile X syndrome. The doctor told us that it comes from repeats in the fragile X chromosome. My son is not using any medication and his blood pressure temperature and breathing were normal during the exam. He also did a blood test. The results came back and showed that his blood sugar urea creatinine calcium sodium potassium chloride CO2 and blood pH were all within the normal range.

Clinical trial: An Open Label Extension Study in Subjects With Fragile X Syndrome

Eligibility criteria:
Inclusion Criteria:

          1. Successfully completed all scheduled visits of the previous protocol ( 22002,
             209FX301, or 209FX302).

          2. A parent,LAR, or caregiver must be willing and able to accompany the subject to all
             study visits, participate in phone calls, complete study assessments, administer study
             medication, and report the subject's condition and medication use to site staff
             members.

          3. Prior to the conduct of any study-specific procedures, the subject must provide
             written informed consent to participate in the study ( if developmentally appropriate)
             or verbal assent and the parent/caregiver/LAR must provide written informed consent.
             If the caregiver attending the clinic visits is not the parents, caregiver, or LAR,
             written consent must also be obtained for the caregiver's participation in the study.

          4. Current treatment with no more than 3 psychoactive medications, including
             anti-epileptics, unless the Medical Monitor is consulted.

          5. Subjects with a history of seizure disorder must have been seizure free for 6 months
             and be taking anti-epileptics, or seizure free for 3 years if not receiving
             anti-epileptic treatment. If currently receiving treatment with anti-epileptics, serum
             concentration levels must be tested and be in therapeutic range.

          6. Negative pregnancy test for females of childbearing potential or be using a medically
             acceptable form of birth control.

        Exclusion Criteria

          1. Subjects with any condition that might interfere with the conduct of the study,
             confound interpretation of the study results, or endanger their own well-being. This
             includes, but is not limited to impairment of renal function, evidence or history of
             malignancy or any significant hematological, endocrine, cardiovascular, respiratory,
             hepatic, or gastrointestinal disease.

          2. Subjects who are currently engaged in illicit drug or alcohol abuse.

          3. Subjects who had a serious adverse event (SAE) while taking STX209 during their
             previous protocol (22002,209FX301,309FX302)that the Investigator considered related to
             STX209, unless approval from the Medical Monitor is obtained.

          4. The occurrence or continuation of any AE or condition during Studies 22002, 209FX301,
             or 209FX302 that, in the opinion of the Investigator, should exclude this subject from
             participating in the open-label extension.

          5. Subjects taking another investigational drug, other than STX209, currently or within
             30 days of Visit 1. Subject must not take any investigational drugs during this study.

          6. Subjects who, in the Investigator's opinion, might not be suitable for the study.

          7. Subjects treated with vigabatrin, tiagabine, or riluzole currently or within 2 weeks
             of Visit 1.

          8. Subjects treated with racemic baclofen currently or within 1 week of Visit 1.
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 5 Years old.
Subject must be at most 50 Years

Eligibility (NLI label): Entailment