Fahr's syndrome

Overview

Fahr's syndrome, also known as familial idiopathic basal ganglia calcification, is a rare neurological disorder characterized by abnormal calcium deposits in areas of the brain that control movement, particularly the basal ganglia and cerebral cortex. The condition can lead to a wide range of motor, cognitive, and psychiatric symptoms. Fahr’s syndrome may occur sporadically or as an inherited disorder, and it is typically identified through neuroimaging.

Causes

The exact cause of Fahr's syndrome varies depending on whether it is inherited or secondary to another condition. Common causes include:

• Genetic mutations: Familial cases are often linked to mutations in genes such as SLC20A2, PDGFB, or PDGFRB, and are typically inherited in an autosomal dominant pattern.

• Metabolic and endocrine disorders: Secondary Fahr’s syndrome can result from conditions like hypoparathyroidism, pseudohypoparathyroidism, hyperparathyroidism, or other disturbances in calcium-phosphorus metabolism.

• Infections and mitochondrial disorders: In rare instances, brain infections or mitochondrial diseases may contribute to abnormal brain calcification.

Symptoms

The symptoms of Fahr's syndrome can vary in severity and presentation, and they usually appear in adulthood. Common symptoms include:

• Movement disorders: Tremors, muscle stiffness, involuntary movements (chorea), and parkinsonism-like features.

• Cognitive impairment: Memory loss, difficulty concentrating, and dementia-like symptoms in advanced cases.

• Psychiatric disturbances: Depression, anxiety, psychosis, or personality changes.

• Seizures: May occur in some individuals, especially in severe cases.

• Speech and swallowing difficulties: Dysarthria and dysphagia may develop due to brain involvement.

Diagnosis

Diagnosis of Fahr’s syndrome is based on clinical evaluation and imaging studies. Diagnostic steps include:

• CT scan or MRI: Brain imaging reveals symmetrical calcifications in the basal ganglia, thalamus, dentate nucleus, and cerebral cortex.

• Blood tests: To evaluate calcium, phosphorus, and parathyroid hormone (PTH) levels, and to rule out metabolic or endocrine causes.

• Genetic testing: In familial cases, testing can identify specific gene mutations associated with primary familial brain calcification.

• Neurological and psychiatric evaluation: To assess the extent of cognitive and motor dysfunction.

Treatment

There is no cure for Fahr's syndrome, and treatment is focused on managing symptoms and underlying causes when applicable. Common approaches include:

• Symptomatic treatment: Use of medications such as antipsychotics, anticonvulsants, antidepressants, or antiparkinsonian drugs depending on the symptoms.

• Correction of metabolic abnormalities: In secondary Fahr’s syndrome, treating the underlying condition such as hypoparathyroidism can help prevent further calcification and reduce symptom progression.

• Rehabilitation therapies: Physical therapy, occupational therapy, and speech therapy to improve function and quality of life.

• Psychiatric care: Counseling and pharmacologic treatment for mood or psychotic symptoms.

Prognosis

The prognosis for individuals with Fahr’s syndrome varies depending on the cause and severity of the condition. In familial cases, the disease typically progresses slowly, but symptoms can significantly impact daily life over time. Early diagnosis and management of secondary causes can improve outcomes and prevent rapid deterioration. Lifespan may not be severely affected in mild cases, but in advanced forms with severe neurological involvement, prognosis may be guarded.