Diseases of the basal ganglia often combine abnormalities of motor control, cognitive impairment, and behavioral change. Some common diseases of the basal ganglia include Huntingtonâ€™s disease, Parkinson disease, and Tourette syndrome. A growing body of evidence has suggested that many of the problems of Lesch-Nyhan disease also result from dysfunction of the basal ganglia. Their difficulties with motor control, dystonia and chorea, are typically associated with dysfunction of the motor circuit of the basal ganglia. Studies of other diseases and animals have linked the problem of self-injurious behavior to the basal ganglia as well. Their pattern of cognitive impairments may reflect dysfunction of the cognitive circuits of the basal ganglia, but may also reflect broad involvement of the cerebral cortex.
Standard brain scans (MRI and CT) of people with Lesch-Nyhan disease often appear normal, but close inspection may reveal shrinkage of two basal ganglia structures, the caudate and putamen. Also more sophisticated scans and biochemical studies have suggested abnormal basal ganglia function. In particular, shortage of dopamine seems to play an important role. Dopamine is a neurotransmittor, a brain chemical which is involved in signalling between brain cells.