Fahr disease is a rare, progressive neurological disorder that is often hereditary. Characterized by deposits of calcium in the basal ganglia and other parts of the brain, Fahr disease causes worsening dementia and the loss of routine motor skills, among other symptoms.
Though calcium is important for good health, this mineral can have harmful effects when it appears in parts of the body where it does not belong. In Fahr disease, abnormal deposits of calcium build up in a region of the brain called the basal ganglia (mainly in a section called the globus pallidus), as well as in other parts of the brain. The basal ganglia is the technical name given to clusters of nerve cells that help to initiate and control movements of the body—for example, reaching for a cup of coffee or taking a step forward while walking. The presence of these calcium deposits (referred to as calcifications) interferes with the working of the brain, causing a variety of debilitating mental and physical symptoms that worsen over time. Aside from the basal ganglia, the calcium deposits associated with Fahr disease often appear in other areas of the brain such as the cerebral cortex.
Two important effects of the disease are dementia and the loss of learned motor skills. People affected by Fahr disease may become overly forgetful and easily confused or disoriented. They have trouble performing relatively simple tasks that require basic hand-eye coordination. Most people with the disease experience slurred speech and problems involving involuntary movements or poor coordination. In addition, personality changes and disorders of mood may develop. In one study of 18 people with Fahr disease, half of the participants had symptoms of obsessive-compulsive disorder, major depression, or bipolar disorder. People with Fahr may have psychotic symptoms, including hallucinations (visual and auditory), a distorted perception of reality, and paranoid delusions.
As the disease progresses, it causes an increasing degree of paralysis. Muscles become stiff and physical movement is restricted. Aside from these symptoms, people with Fahr disease may experience specific movement disorders: slow, twisting movements of the hands and feet (athetosis) and jerky, rapid movements that resemble spasms (chorea). Vision may also be affected. Because the disease can weaken nerves that carry signals from the eyes to the brain, people with Fahr disease may experience partial or almost complete vision loss. Ear infections have also been reported.
The underlying cause of Fahr disease is unknown. For this reason, it is described as an idiopathic disorder. Fahr disease is often referred to in the medical literature as idiopathic basal ganglia calcification (IBGC). Less common names for the disease include cerebrovascular ferrocalcinosis, non-arteriosclerotic cerebral calcifications, and striopallidodentate calcinosis.
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Author Info: Greg Annussek, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Genetic Disorders Part I, 2002 |