Sign Up for a Free Account
  • Updated 12.27.2023
  • Released 06.25.2007
  • Expires For CME 12.27.2026

Idiopathic basal ganglia calcification



Idiopathic basal ganglia calcification (IBGC), previously widely misrepresented as Fahr disease, is an inherited neuropsychiatric disorder, characterized by bilateral and usually symmetrical calcifications predominantly in the basal ganglia, but also extending to the cerebellum, thalamus, and subcortical white matter. Although a large proportion of patients remain asymptomatic, parkinsonism and other movement disorders appear to be the most common clinical manifestation, followed by psychiatric symptoms, cognitive impairment, and ataxia. CT scan is considered more sensitive than MRI for detecting calcifications. In this article, the authors discuss the etiology, pathogenesis, genetics, classification, and clinical manifestations of idiopathic basal ganglia calcification. A comprehensive list of disorders causing secondary brain calcification is provided (hypoparathyroidism being the most common).

Key points

• Idiopathic basal ganglia calcification may clinically manifest as movement disorders such as parkinsonism, ataxia, chorea, tremor, dystonia, athetosis, or orofacial dyskinesia. However, approximately one third of patients may be asymptomatic.

• The term idiopathic basal ganglia calcification may be used only after excluding secondary causes of basal ganglia calcification.

• Idiopathic basal ganglia calcification is inherited in an autosomal dominant or recessive pattern, with seven causative genes identified. However, several cases occur de novo.

• Head CT is the most sensitive imaging modality to assess for idiopathic basal ganglia calcification.

Historical note and terminology

Basal ganglia calcifications involving the striatum, pallidum, with or without deposits in dentate nucleus, thalamus, and white matter have been reported in asymptomatic individuals and in a variety of neurologic conditions (68; 49; 79). Since the first reports of such calcifications, up to 35 descriptive terms have been used for the same disease. This has added to the confusion regarding the etiology and clinical manifestations of idiopathic basal ganglia calcification compared to other disorders with similar radiographic appearance (49).

When basal ganglia calcifications are thought to be idiopathic (after appropriate search for secondary causes), the term idiopathic basal ganglia calcification (IBGC) is used. This was previously referred to as Fahr disease, but this eponym fell out of favor as Fahr was neither the first to describe the disorder nor did he contribute significantly to its understanding (49). As genetic underpinnings of idiopathic basal ganglia calcification have been identified, many authors have started using the term “primary familial” instead of “idiopathic” (82; 37; 83). Idiopathic basal ganglia calcification is typically inherited in an autosomal-dominant pattern, but if family history or genetic testing cannot be obtained, the term idiopathic may still be appropriate. Of note, incidental findings of basal ganglia calcification may be present in up to 20% of healthy people (these calcifications are typically punctate, confined to pallidum, and increase with age) (96). Therefore, the term idiopathic basal ganglia calcification should only be used if there are appropriate accompanying clinical symptoms, or the calcifications are significant or if a relevant genetic mutation has been identified.

Secondary brain calcification, conversely, has been reported in a variety of genetic, developmental, metabolic, infectious, and other conditions (see Table 1) (49). To avoid confusion the term “secondary” should be used to differentiate it from idiopathic basal ganglia calcification (78).

A historical description of basal ganglia calcification is provided by Manyam (49). Briefly, in 1850, Delecour first observed bilateral calcifications on brain histopathology from a 56-year-old man who had stiffness and weakness of lower extremities with tremor. In 1855, Bamberger described the histopathologic entity of calcifications in a woman who had mental retardation and seizures (07). It was only in 1930 that German Neuropathologist Karl Fahr described an 81-year-old man with a long history of dementia, “immobility without paralysis,” with pathologic findings of “rough granular cortex and calcifications in centrum semiovale and striatum” (26). Fahr’s name subsequently became associated with all forms of bilateral calcifications in the basal ganglia. Fritzsche gave the first roentgenographic description of the condition in 1935 (49).

Given the hallmark of this disease is calcification of the basal ganglia, and the term “idiopathic basal ganglia calcification” is well established in the literature, as well as the OMIM registry, that will be the term used in this review.

This is an article preview.
Start a Free Account
to access the full version.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Questions or Comment?

MedLink®, LLC

3525 Del Mar Heights Rd, Ste 304
San Diego, CA 92130-2122

Toll Free (U.S. + Canada): 800-452-2400

US Number: +1-619-640-4660



ISSN: 2831-9125