Clemastine Fumarate in the Treatment of Neurodevelopmental Delays in Williams Syndrome

Inclusion Criteria:

1. Age 3-6 years old;
2. Positive fluorescence in situ hybridization (FISH) test confirmed Williams syndrome;
3. GTF2I gene mutation was detected by whole exon;
4. Heart safety variables are normal (e.g. normal ECG, blood pressure 120-129/80-84)

Exclusion Criteria:

1. WS patients with other gene mutations;
2. Used antihistamines, monoamine oxidase inhibitors, barbiturates and sedatives, as wellas drugs affecting cognitive behavior, limb movement, white matter myelin, and MRIwithin 2 months before enrollment;
3. Patients with narrow-angle glaucoma, narrow peptic ulcer, pyloroduodenal obstruction,symptomatic prostatic hypertrophy and bladder neck obstruction; Accompanied by severeimmunodeficiency disease;
4. Allergic to Clomastine fumarate or other arylalkylamine antihistamines or anyreceptor;
5. According to the recent interpretation of MRI and neuroradiology experts or WS, thereare obvious brain lesions that are not related to WS disease;
6. Clinically significant metabolic, hematological, liver, immune, urinary, endocrine,neurological, pulmonary, psychiatric, skin, allergic, renal, or other major diseasesthat may affect the interpretation of study findings or patient safety in WS'sjudgment;