Friedreich Ataxia

What is Friedreich ataxia?

Friedreich ataxia is a genetic condition that damages nerve tissue, causing a loss of muscle coordination (ataxia) that worsens over time. Other characteristics of this condition include the gradual loss of strength and sensation in arms and legs, muscle stiffness (spasticity) in the limbs, and impaired speech. Friedreich ataxia may also affect heart function.

Typically, signs and symptoms of Friedreich ataxia first appear in childhood or the early teens. Poor balance when walking and slurred speech are often the initial symptoms. About 25 percent of cases, however, occur after age 25. These cases are classified as late-onset Friedreich ataxia (LOFA), with onset between 26 and 39 years, or very late-onset Friedreich ataxia (VLOFA), which begins at age 40 or older.

How common is Friedreich ataxia?

Friedreich ataxia is estimated to affect 1 in 40,000 people.

What genes are related to Friedreich ataxia?

Mutations in the FXN gene cause Friedreich ataxia.

Friedreich ataxia is caused by a mutation in which a DNA segment, known as the GAA triplet repeat, is abnormally expanded within the FXN gene. Normally, this segment is repeated 5 to 33 times within the gene. In people with Friedreich ataxia, however, the GAA segment is repeated 66 to more than 1,000 times. The abnormally expanded GAA segment disrupts the production of a protein called frataxin, which drastically reduces the amount of this protein in cells. Certain nerve and muscle cells cannot function properly with a shortage of frataxin, leading to the signs and symptoms of Friedreich ataxia.

How do people inherit Friedreich ataxia?

This condition is inherited in an autosomal recessive pattern, which means two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.

What other names do people use for Friedreich ataxia?

  • FA - Friedreich ataxia
  • FRDA
  • Hereditary spinal ataxia
  • Hereditary Spinal Sclerosis
  • Spinocerebellar Ataxia, Friedreich

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