Safety and Efficacy of TSHA-102 in Pediatric Females with Rett Syndrome (REVEAL Pediatric Study)

Inclusion Criteria:

* Participant has a confirmed diagnosis of classical/typical Rett Syndrome with a documented mutation of the MECP2 gene that results in loss of function.
* Participant is between ≥5 to ≤8 years of age at the time of consent.
* Participant must be up to date with all relevant local vaccination requirements, with last vaccination dose received at least 42 days prior to the start of the immunosuppression regimen.
* Participant's parent/caregiver must be willing to allow participant to receive blood or blood products for the treatment of an AE if medically needed.

Exclusion Criteria:

* Participant has another neurodevelopmental disorder independent of the MECP2 gene loss of function mutation, or any other genetic syndrome with a progressive course.
* Participant has a history of brain injury that causes neurological problems.
* Participant had grossly abnormal psychomotor development in the first 6 months of life.
* Participant has a diagnosis of atypical Rett syndrome.
* Participant has an MECP2 mutation that does not cause Rett syndrome.
* Participant requires non-invasive and invasive ventilatory support.
* Participant has contraindications for IT administration of TSHA-102 or lumbar puncture procedure, other medical conditions, or contraindications to any medications required for IT administration.
* Participant has acute or chronic hepatitis B or C infections.

For more information on this trial, visit clinicaltrials.gov.