Coloured 3D computed tomography (CT) scan of the head and brain of a patient with Fahr syndrome. Fahr syndrome, or idiopathic basal ganglia calcification, is a hereditary neurological disorder that causes abnormal deposits of calcium to accumulate in areas of the brain that control movement, primarily the basal ganglia (centre) and the cerebral cortex. The condition causes progressive neurological deterioration, generally resulting in disability and death.