Fahr disease is a neurological disorder characterized by pathological, abnormal calcium deposits in the Brain. These deposits can lead to a variety of neurological and psychiatric symptoms. The condition may be idiopathic or occur secondarily as a consequence of other diseases.
Classification
Patients with Fahr disease can be divided into three groups:
Young patients with pronounced calcifications (idiopathic Fahr disease)
Patients with hypoparathyroidism
Older patients with minor calcifications
History
The disease was first described in 1930 by the German neurologist Theodor Fahr[^4].
Epidemiology
Fahr disease is a rare disorder with an estimated prevalence of less than 1 case per 1,000,000 people. The disease typically manifests in the third or fourth decade of life[^2].
Localization
Fahr disease is characterized by abnormal calcium deposits in areas of the brain that control movement[^5]:
Subcortical white matter
Symptoms
The symptoms of Fahr disease are varied and depend on the location and extent of the calcifications. Common symptoms include movement disorders such as tremor and impaired fine motor skills[^1]. Other possible symptoms include speech disorders, memory impairment, and neuropsychiatric symptoms [^11].
Imaging
The extent of calcifications in Fahr disease can be optimally visualized with CT imaging.
Molecular genetics
Fahr disease is most commonly inherited as an autosomal dominant trait, but it can also be inherited as an autosomal recessive trait or occur sporadically[^6]. A locus on 14q (IBGC1) is frequently described as being involved. A second locus on chromosome 8 and a third on chromosome 2 have also been identified [^7] [^8] [^9]. A loss-of-function mutation in the gene encoding the type III sodium-dependent phosphate transporter 2 (SLC20A2) on chromosome 8 has also been described at the molecular level as a possible basis for the pathophysiology of this disease[^10].