This study explores how safe and effective a new injection, called NouvNeu001, is for people with Early-onset Parkinson's Disease (EOPD). Parkinson's Disease is a brain disorder that affects movement, causing tremors, stiffness, and balance problems. The study will use stereotactic neurosurgery, a type of surgery that helps doctors precisely target areas in the brain. Participants will receive the injection into a part of the brain called the bilateral putamen and take medication to prevent the body from rejecting the treatment for about 24 to 36 weeks. The study will check if this treatment helps improve movement and other symptoms.

• The study involves a brain surgery, which carries risks.
• Participants will take extra medications for up to 36 weeks.
• Eligibility requires being 18-70 years old and diagnosed with EOPD.

Participants must not have certain health conditions, like severe heart disease or active infections. They also shouldn't have had certain surgeries or treatments before. The study is not suitable for those with poor health or compliance issues.