A Study to Evaluate the Tolerability, Safety and Efficacy of VGM-R02b

Inclusion Criteria: 1. Subjects must be ≤ 6 years; 2. History of diagnosis of GA-I, and confirmed by gene mutation analysis with biallelic GCDH mutation; 3. At the time of screening, there was one of the obvious neurological manifestations associated with the following diseases, including macrocephaly, dystonia, and motor/intellectual development Poor fertility, epilepsy, abnormal EEG; 4. Those who are receiving standard treatment recommended by the guidelines and whose symptoms remain poorly controlled by the investigator; 5. Plasma GA and 3-OHGA levels were higher than the normal range during screening; Exclusion Criteria: 1. Participation in gene therapy or stem cell transduction therapy at any time prior to screening for this trial or participation in any other clinical trial within 3 months prior to screening; 2. Recurrent seizures that are not suitable for surgery, based on Investigator judgment; 3. Current severe liver or kidney or cardiovascular disease or coagulation dysfunction, autoimmune deficiency, or uncontrolled autoimmune disease or need immunosuppressive long-term treatment, poorly controlled diabetes (HBA1C ≥7% at screening) or high blood pressure; 4. Active viral infection (includes HIV or serology positive for hepatitis B or C or syphilis); 5. Presence or history of malignancy; 6. Received systemic immunosuppressive therapy within 3 months prior to screening; 7. Received vaccine within 4 weeks prior to administration or plan to receive vaccine within 1 year after administration; 8. Plan to receive surgery during the study; 9. Current using medications including, drugs, herbal or OTC medications that strongly inhibit or induce CYP3A4 or P-glycoprotein (P-gp), e.g., metoclopramide, grapefruit juice, ketoconazole, erythromycin; 10. Abnormal brain structure, not suitable for lateral ventricle administration; 11. Abnormal laboratory test results, which are judged by the investigator not suitable for surgery; 12. History of systemic hypersensitivity reaction to investigational product, the excipients contained in the formulation, or prophylactic immunosuppressant; 13. Contraindicated use of corticosteroids and sirolimus; 14. Contraindicated with general anesthesia or sedation; 15. As judged by the investigator, unable to perform lateral ventricle puncture or Ommaya capsule implantation or lumbar puncture; 16. Unable to perform CT or MRI; 17. Poor compliance; 18. Any other situation where, judged by the investigator, the subject is not suitable for participating in this study.