What is Fahr syndrome (Idiopathic Basal Ganglia Calcification)?

From the Guidelines

Fahr syndrome is a rare neurological disorder that requires a comprehensive management approach focusing on symptomatic relief and quality of life improvement, rather than cure, as the primary goal. The condition is characterized by abnormal calcium deposits in the brain, particularly in the basal ganglia, which can lead to a range of neurological and psychiatric symptoms including movement disorders, cognitive decline, seizures, headaches, and psychiatric manifestations such as mood disorders and psychosis 1. These calcifications can be detected through brain imaging, with CT scans being particularly effective, and diagnosis also involves clinical evaluation and genetic testing to identify potential genetic causes, including mutations in genes like SLC20A2, PDGFRB, and PDGFB.

Key Considerations

• The condition typically appears in middle adulthood but can develop at any age, emphasizing the need for a broad diagnostic consideration in patients presenting with neurological or psychiatric symptoms.
• Treatment is primarily symptomatic and supportive, focusing on managing specific manifestations like movement disorders with medications such as levodopa, anticonvulsants for seizures, and psychiatric medications for behavioral symptoms 1.
• There is no cure for the underlying calcification process, making ongoing management and support crucial for maintaining the patient's quality of life.
• Patients require multidisciplinary care involving neurologists, psychiatrists, and genetic counselors to address the complex nature of the disorder and its varied manifestations.

Management and Prognosis

• The prognosis varies widely, with some patients experiencing slow progression while others develop more severe disability, highlighting the importance of early diagnosis and consistent symptom management.
• Early diagnosis and consistent symptom management are essential for maintaining quality of life for affected individuals, as they allow for the implementation of targeted interventions to mitigate the impact of the disease on the patient's daily life and overall well-being 1.
• Ongoing research into the genetic and molecular underpinnings of Fahr syndrome may offer future avenues for more targeted therapies, but currently, the focus remains on supportive care and symptom management.

From the Research

Definition and Characteristics of Fahr Syndrome

• Fahr syndrome is a rare neurological disorder characterized by abnormal calcified deposits in basal ganglia and cerebral cortex 2.
• Calcified deposits are made up of calcium carbonate and calcium phosphate, and are commonly located in the Basal Ganglia, Thalamus, Hippocampus, Cerebral cortex, Cerebellar Subcortical white matter and Dentate Nucleus 2.
• The syndrome is also known as Idiopathic Basal Ganglia Calcification (IBGC) or Fahr's disease 3.

Etiology and Associations

• The etiology of Fahr syndrome does not identify a specific agent, but associations with a number of conditions have been noted, including endocrine disorders, mitochondrial myopathies, dermatological abnormalities, and infectious diseases 2.
• Hypoparathyroidism is a common association with Fahr syndrome, and can lead to hypocalcemia and hyperphosphoremia 4, 5.
• Primary hypoparathyroidism can cause calcification of the basal ganglia due to abnormal phosphocalcic metabolism 5.

Clinical Manifestations

• Clinical manifestations of Fahr syndrome incorporate a wide variety of symptoms, ranging from neurological symptoms of extrapyramidal system to neuropsychiatric abnormalities of memory and concentration to movement disorders including Parkinsonism, chorea, and tremors 2.
• Psychotic symptoms, such as auditory and visual hallucinations, complex perceptual distortions, delusions, and fugue state, can also occur in patients with Fahr syndrome 4.
• Seizures are a common presenting symptom of Fahr syndrome, and can be associated with hypocalcemia and abnormal electroencephalogram findings 5, 3.

Diagnosis and Treatment

• Diagnostic criteria for Fahr syndrome include bilateral calcification of basal ganglia, progressive neurologic dysfunction, absence of biochemical abnormalities, absence of an infectious, traumatic or toxic cause, and a significant family history 2.
• Imaging modalities for diagnosis include CT, MRI, and plain radiography of skull, as well as blood and urine testing for hematologic and biochemical indices 2.
• Treatment of Fahr syndrome is mainly focused on symptomatic relief and eradication of causative factors, and may include calcium supplementation, vitamin D therapy, and antipsychotic medication 4, 5, 3.
• Early diagnosis and treatment can reverse the calcification process leading to complete recovery of mental functions, and families with a known history of Fahr syndrome should be counseled prior to conception to prevent the birth of affected babies 2.