• Disease Status: Diagnosis of H3K27M mutant diffuse midline glioma (DMG)

• H3K27M or H3K27I mutation. Confirmed by CLIA test.

• Age: Greater than or equal to 2 year of age and less than or equal to 60 years of age.

• Prior Therapy:

‣ At least 4 weeks following completion of standard upfront radiation therapy.

⁃ At least 3 weeks post chemotherapy or 5 half-lives, whichever is shorter, must have elapsed since any prior systemic therapy, except for systemic inhibitory/stimulatory immune checkpoint therapy that requires 3 months.

• Performance Status:

• Subjects \> 16 years of age: Karnofsky ≥ 60% OR Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1; Subjects ≤ 16 years of age: Lansky scale ≥ 60%.

• Subjects who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score.

• Normal Organ and Marrow Function (supportive care is allowed per institutional standards, i.e. filgrastim, transfusion) i. ANC ≥ 1000/uL ii. Platelet count ≥ 100,000/uL iii. Absolute lymphocyte count ≥ 150/uL iv. Hemoglobin ≥ 8 g/dL v. Adequate renal, hepatic, pulmonary and cardiac function defined as:

• \- Creatinine within institutional norms for age (i.e.

• ≤ 2 mg/dL in adults or according to table below in children \<18 years) OR creatinine clearance (as estimated by Cockcroft Gault Equation) ≥ 60 mL/min

• Serum ALT/AST ≤ 3.0 ULN (grade 1)

⁃ Total bilirubin ≤ 1.5 mg/dl, except in subjects with Gilbert's syndrome.

⁃ Cardiac ejection fraction ≥ 45%, no evidence of physiologically significant pericardial effusion as determined by an ECHO, and no clinically significant ECG findings

⁃ Baseline oxygen saturation \> 92% on room air

• Pregnancy Test Females of childbearing potential must have a negative serum or urine pregnancy test (females who have undergone surgical sterilization are not considered to be of childbearing potential) or NA

• Contraception Subjects of child-bearing or child-fathering potential must be willing to practice birth control from the time of enrollment on this study and for four (4) months after receiving the preparative regimen or for as long as GD2CART cells are detectable in peripheral blood or CSF.

• Ability to give informed consent. All subjects ≥ 18 years of age must be able to give informed consent. For subjects \<18 years old their legal authorized representative (LAR) (i.e. parent or guardian) must give informed consent. Pediatric subjects will be included in age appropriate discussion and written assent will be obtained for those \> 7 years of age, when appropriate. If a minor becomes of age during participation of this study, he/she will be asked to reconsent as an adult.