Fahr disease or familial idiopathic basal ganglia calcification (IBGC)
Incidence
Most families with IBGC show an autosomal dominant inheritance pattern of inheritance, and most patients are symptomatic. Autosomal recessive also seen when reported in children..
Clinical Characteristics
Fahr disease, or familial idiopathic basal ganglia calcification (IBGC), is characterized by bilateral basal ganglia calcification and can lead to progressive dystonia, parkinsonism, and neuropsychiatric manifestations. Most families with IBGC show an autosomal dominant inheritance pattern of inheritance, and most patients are symptomatic. Typically, age at onset of clinical symptoms is 30 to 60 years. The core clinical features of IBGC are dysarthria, extrapyramidal signs, and ataxia. The most common area of calcification is the globus pallidus. However, additional areas of involvement may include the putamen, caudate, dentate, thalamus, and cerebral white matter. Calcification can also occur in the cerebellum and internal capsule. The calcium deposits occur in the extracellular and extravascular space, often surrounding capillaries. Even within families, the expression of IBGC is varied. It is not clear whether the CNS calcification in IBGC is a metastatic deposition, secondary to local disruption of the blood-brain barrier, or is due to a disorder of neuronal calcium metabolism. Fahr disease is also called a number of different disorders in children that have little in common, but tend to have a severe clinical outcome.The clinical evolution is that of a degenerative rather than a developmental disorder. Progressive deterioration of mentality and loss of motor accomplishments take place and symmetrical spastic paralysis and sometimes athetosis appear, progressing to a decerebrate state. The head is small and round. Optic atrophy may be present. Mineral deposits are distributed throughout the cerebral cortex, basal ganglia, dentate nucleus, subthalamus and red nucleus with cell loss in these areas. Calcification probably occurs in areas of demyelination and lipid deposition.
Precipitants
none.
Provocation Tests
none
Diagnostic Procedures
It is a clinical diagnosis. The entity is not a single disease when seen in children.