Friedreich’s ataxia causes nervous system damage and movement problems. It usually begins in childhood and leads to impaired muscle coordination (ataxia) that worsens over time. Friedreich’s ataxia is caused by a defect (mutation) in a gene labeled FXN. Symptoms typically begin between the ages of 2 and 15 years, although they sometimes appear in adulthood. The first symptom to appear is usually gait ataxia, or difficulty walking. People can also experience a loss of sensation in their hands and feet.