Idiopathic basal ganglia calcifications: an atypical presentation of PKAN.

Background: We report a patient with pantothenate kinase-associated neurodegeneration presenting as idiopathic basal ganglia calcifications, previously known as Fahr's disease.

Methods: A teenage girl presented with slowly progressive dystonia. Her brain magnetic resonance imaging scan revealed T1 and T2 hypointensities in both globus pallidi, and no eye-of-the-tiger sign. Computed tomography showed dense globus pallidi calcifications. Metabolic evaluation was negative. The patient was diagnosed with idiopathic basal ganglia calcifications, a poorly understood syndrome of unknown cause. Whole exome sequencing was performed.

Results: The patient was found to have two mutations in the pantothenate kinase 2 (PANK2) gene that have been previously associated with pantothenate kinase-associated neurodegeneration: a paternally inherited p.G521R and maternally inherited p.T528M. No deleterious changes were identified in genes associated with idiopathic basal ganglia calcifications or dystonia.

Conclusions: Pantothenate kinase-associated neurodegeneration should be considered in patients with idiopathic basal ganglia calcifications, especially when findings are confined to the globus pallidus.