Autoantibodies directed against the basal ganglia of the brain are associated with a variety of neuropsychiatric and movement disorders in both children and adults.
The basal ganglia of the brain refers to the caudate nucleus, putamen and globus pallidus. These structures, which are found in the neurons of the brain, control voluntary movements. Anti-basal ganglia antibodies (ABGA) are a type of anti-neuronal autoantibody to the basal ganglia associated with the development of movement disorders (dystonia, motor and vocal tics, chorea, Tourette's syndrome, Parkinson’s disease) in adults and psychiatric disturbances in children, including Sydenham’s chorea and PANDAS syndrome which refers to Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus infections.
Association with Infection
Studies show a high association between respiratory infection, particularly group A beta-hemolytic streptococcal and herpes zoster infections, and the subsequent development of anti-basal ganglia antibodies. An autoimmune mechanism involving molecular mimicry has been proposed for a variety of movement disorders in both children and adults that are characterized by the presence of anti-basal ganglia antibodies. In this case, bacteria mutate to take on the appearance of ganglia, which are then targeted during the immune response.
Who is Affected?
Children as well as adults are reported to develop neuropsychiatric and movement disorders associated with anti-basal ganglia antibodies and in some cases inflammation of the basal ganglia (seen on imaging studies). In studies of adults with new onset movement disorders, the mean age has been reported to be 36 years. In adults, suspected triggers include trauma, infection, encephalitis and cocaine use.
Associated Conditions
Early studies showed the presence of the anti-basal ganglia antibodies in obsessive compulsive and emotional disorders such as PANDAS and Sydenham’s chorea. More recent studies show that these antibodies also occur in adult-onset movement disorders as well as an encephalitis lethargica-like illness that’s reported to occur following streptococcal infection; restless leg syndrome; and Parkinson’s disease.
Blood and Cerobrospinal Fluid (CSF) Tests
There are a number of different methods available for testing anti-neuronal as well as anti-basal ganglia antibodies. However, testing methods differ in terms of sensitivity and the specific antigen targets associated with these antibodies. Consequently, the pathology of anti-basal ganglia antibodies is still considered controversial with some researchers considering these antibodies pathogenic only if they’re proven to react with brain tissue (the basis for most neuronal antibody tests) or if they’re present in cerebrospinal fluid.
Resources:
M Edwards, R Dale, A Church, G Giovannoni, and K Bhatia, A dystonic syndrome associated with anti-basal ganglia antibodies, J Neurol Neurosurg Psychiatry, Jun 2004; 75(6):914-916.
D Martino and G Giovannoni, Antibasal ganglia antibodies and their relevance to movement disorders, Current Opinions in Neurology, Aug 2004; 17(4): 425-432.
H Siunger, C Loiselle, O Lee, K Minzer, S Swedo, and F Grus, Anti-basal ganglia antibodies in PANDAS, Movement Disorders Apr 2004; 19(4): 406-415.
