Control Cohort CTRL COH

This study is enrolling a control group of patients with certain neurological or non-neurological conditions to help researchers better understand rare brain diseases. By collecting samples and data from people with conditions like Parkinson's disease, ALS, glioblastoma, and certain cancers, researchers can compare them against patients with unusual neurological syndromes. **You may be eligible if...** - You have one of the following diagnoses: Parkinson's disease, ALS (amyotrophic lateral sclerosis), glioblastoma (brain cancer), a non-neurological cancer (lung, breast, ovarian, melanoma, or thymoma), or rheumatoid arthritis - You are able to give informed consent **You may NOT be eligible if...** - You refuse or are unable to give consent - You have a condition consistent with a paraneoplastic neurological syndrome or autoimmune encephalitis (a type of brain inflammation caused by the immune system) - You are under legal guardianship Talk to your doctor to see if this trial is right for you.