Another subset of rarer movement disorders are multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). A project using tissue from donors with MSA has demonstrated that a protein present in Lewy bodies called LRRK2 was also present early in the formation of glial cytoplasmic inclusions (GCI), the pathological characteristic of MSA. LRRK2 may be an important factor in the disease as its expression increased with the amount of GCIs, myelin degradation and cell loss. PSP can be difficult to treat as it often exhibits an unsatisfactory response to levadopa therapy. More widespread loss of cells of the extranigral A10 region of the substantia nigra was recently discovered (compared to PD cases, who usually have an adequate response to levadopa), indicating that these cells may be required for a good response to levadopa therapy.
