Fahr’s disease is a rare neurological disorder characterized by the abnormal accumulation of calcium deposits within specific brain regions. These mineral buildups can disrupt normal brain function.
Understanding Fahr’s Disease
Fahr’s disease is defined by calcium and other mineral deposits, predominantly in brain areas such as the basal ganglia, thalamus, and cerebellum. Calcifications can also extend to the hippocampus and cerebral cortex. These deposits often appear as small granules or nodules within the brain tissue.
The disease was first described by German neurologist Karl Theodor Fahr in 1930. While sometimes referred to as Fahr’s syndrome, “Fahr’s disease” is reserved for cases where no other underlying cause for the calcifications is identified. It is classified as a progressive neurodegenerative disorder, meaning its features can worsen over time.
Uncovering the Causes
Fahr’s disease can stem from genetic predispositions (primary forms) or be linked to other medical conditions (secondary forms). Primary Fahr’s disease is inherited, often in an autosomal dominant pattern. Genetic mutations in specific genes, including SLC20A2, PDGFRB, PDGFB, XPR1, MYORG, JAM2, and NAA60, have been identified as causes. SLC20A2 is the most commonly implicated gene, affecting phosphate transport.
Secondary forms of brain calcification arise from various underlying health issues. Parathyroid dysfunction, particularly hypoparathyroidism, is a frequent cause. Other contributing factors include certain mitochondrial disorders, infections, and exposure to toxic substances. In some instances, the cause remains undetermined (idiopathic).
Identifying the Symptoms
The clinical presentation of Fahr’s disease can vary significantly among individuals, reflecting the diverse locations and extent of brain calcifications. Motor symptoms are common, including movement disorders such as dystonia (sustained muscle contractions) and parkinsonism (tremors, rigidity, and slowed movements). Individuals may also experience ataxia (unsteadiness and balance issues) or chorea (involuntary, jerky movements). Difficulties with speech (dysarthria) and gait disturbances are common.
Cognitive impairments include memory loss, executive dysfunction, and a progressive decline in mental abilities, sometimes leading to dementia. Psychiatric manifestations include mood disorders like depression and anxiety, psychosis, and personality changes. Seizures and headaches are other potential symptoms. Onset typically occurs between the 40s and 60s, though it can appear earlier.
Diagnosis and Management Approaches
Diagnosing Fahr’s disease primarily relies on neuroimaging. Computed tomography (CT) scans are effective for visualizing calcium deposits, being more sensitive than magnetic resonance imaging (MRI). MRI can also assess brain tissue impact and rule out other conditions.
Genetic testing is important when a primary, inherited form is suspected, focusing on genes like SLC20A2 and PDGFRB. Blood and urine tests exclude secondary causes by checking for metabolic abnormalities, such as imbalances in calcium and parathyroid hormone levels, or exposure to heavy metals. There is no cure for Fahr’s disease; treatment focuses on managing symptoms and providing supportive care.
Symptomatic treatments may involve medications to address movement disorders, although responses to drugs like levodopa can be variable. Antidepressants or neuroleptic medications help manage psychiatric symptoms, and anticonvulsants are prescribed for seizures. Supportive therapies, including physical therapy, occupational therapy, and speech therapy, help individuals maintain or improve functional abilities and quality of life. These therapies can assist with motor control, daily activities, and communication challenges.