Over time, muscles begin to weaken and waste away, especially in the feet, lower legs, and hands, and deformities develop. Other symptoms include loss of tendon reflexes, especially in the knees and ankles. There is often a gradual loss of sensation in the extremities, which may spread to other parts of the body. Other symptoms that may occur include chest pain, shortness of breath, and heart palpitations. About 20 percent of people with Friedreich's ataxia develop carbohydrate intolerance and 10 percent develop diabetes mellitus.
Some people lose hearing or eyesight.
The rate of progression varies from person to person. Generally, within 15 to 20 years after the appearance of the first symptoms, the person is confined to a wheelchair, and in later stages of the disease, individuals become completely incapacitated. Life expectancy is greatly affected, and most people with Friedreich's ataxia die in early adulthood if there is significant heart disease, the most common cause of death. However, some people with less severe symptoms of Friedreich's ataxia live much longer. Doctors diagnose Friedreich's ataxia by performing a careful clinical examination, which includes a medical history and a thorough physical examination.