Friedreich ataxia is an autosomal recessive disorder resulting from a GAA triplet repeat expansion in FXN
, the frataxin gene. It is a progressive neurodegenerative disease that causes degeneration of the spinal cord and peripheral nerves. Onset of signs and symptoms is typically in childhood to teens, although up to a quarter of patients develop the disease after age 25. They include ataxia and difficulty walking, dysarthria, sensory loss (particularly proprioception and vibration), weakness, absent reflexes, high-arched feet, and hearing or vision problems. It is associated with heart disease, including cardiomyopathy or arrhythmias, diabetes, and scoliosis
, which may lead to respiratory problems. It does not affect cognitive function. Life expectancy may be shortened, especially in cases with concomitant heart disease. The incidence in the United States and Europe is about 1 in 40 000.