Basal ganglia calcifications (Fahr's syndrome): related conditions and clinical features

Abstract

Basal ganglia calcifications could be incidental findings up to 20% of asymptomatic patients undergoing CT or MRI scan. The presence of neuropsychiatric symptoms associated with bilateral basal ganglia calcifications (which could occur in other peculiar brain structures, such as dentate nuclei) identifies a clinical picture defined as Fahr's Disease. This denomination mainly refers to idiopathic forms in which no metabolic or other underlying causes are identified. Recently, mutations in four different genes (SLC20A2, PDGFRB, PDGFB, and XPR1) were identified, together with novel mutations in the Myogenic Regulating Glycosylase gene, causing the occurrence of movement disorders, cognitive decline, and psychiatric symptoms. On the other hand, secondary forms, also identified as Fahr's syndrome, have been associated with different conditions: endocrine abnormalities of PTH, such as hypoparathyroidism, other genetically determined conditions, brain infections, or toxic exposure. The underlying pathophysiology seems to be related to an abnormal calcium/phosphorus homeostasis and transportation and alteration of the blood-brain barrier.

Keywords: Basal ganglia; Brain calcinosis; Fahr’s syndrome; Hypoparathyroidism.

Fig 1

Brain MRI showing T1-w hyperintensity in basal ganglia (a) and severe T2*-GRE hypointensities in the same regions (b). Brain CT scan showing diffuse symmetric calcifications involving basal ganglia (c), and dentate nucleus (d). GRE gradient recalled echo, FLAIR fluid-attenuated inversion recovery