Friedreich ataxia is an autosomal recessive inherited polyneuropathy (damage to multiple nerves). The symptoms are caused by degeneration of structures in the cerebellum and spinal cord responsible for coordination, muscle movement, and some sensory functions.
Symptoms generally begin in childhood before puberty. Early symptoms include an unsteady gait (ataxia), changes in speech (dysarthria), loss of reflexes, and jerky eye movements (nystagmus).
Abnormal muscle control and tone lead to spinal changes and scoliosis or kyphoscoliosis may develop. Individuals with Friedreich's ataxia may also have hammer toe and high arches (pes cavus).
Heart disease usually develops and may progress into heart failure. Death may result from heart failure or dysrhythmias that will not respond to treatment.
Diabetes may develop in later stages of the disease in up to one third of patients.
Friedreich ataxia results from lack of a specific protein (frataxin) in cells of the brain, nerves, heart and pancreas. The gene encoding this protein is susceptible to a particular kind of DNA mutation.
That mutation is called triplet repeat expansion, and it is easily and reliably tested for in patient DNA from blood sample. Usually an affected person has inherited mutated (expanded) copies of the gene from both parents. That is to say, Friedreich ataxia is an autosomal recessive disease.
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