The goal of this interventional study is to learn about the efficacy and safety of Esketamine for treating children with Rett syndrome (RTT).

The main questions it aims to answer are:

• whether Esketamine treatment is effective in improving symptom severity for RTT.
• whether Esketamine is safe in the treatment of RTT. Participants will receive a weekly intravenous infusion of Esketamine for five weeks and will be assessed for disease severity and drug safety.

Inclusion Criteria:

• Classic/typical RTT
• Causing mutation in MECP2 gene
• Stable pattern of seizures, or has had no seizures at least 8 weeks

Exclusion Criteria:

• Use of other drugs that interact with Esketamine: thyroxine, meglumine diatrizoate, aminophylline, diazepam or midazolam, drugs for antihypertension or central nervous depressants, halogenated general anesthetics (e.g., halothane), tubocurarine, atracurium
• Condition with hypertension, high cerebrospinal fluid pressure, and high intraocular pressure
• Unstable systemic illness other than Rett syndrome: current clinically significant cardiovascular, endocrine (such as hypo- or hyperthyroidism, type 1 diabetes, or uncontrolled type 2 diabetes), renal, hepatic, respiratory, or gastrointestinal disease (such as celiac disease or inflammatory bowel disease), or major surgery planned during the study
• Clinically important variations in medication use

all collected IPD, all IPD that underlie results in a publication

starting 6 months after publication，for one year