Friedreich ataxia is a progressive neurodegenerative disorder with onset before puberty. The spinocerebellar tracts, dorsal columns, pyramidal tracts, cerebellum, medulla, and optic radiation, may all be involved. The outstanding symptom is ataxia with prominent involvement of gait and limbs. Muscle weakness, extensor plantar responses, and absent lower limb reflexes are usually present. Dysarthria is usually notable. Sensory signs include impairment of position and vibratory senses. ‘Twitching’ in limbs and digits is often noted and ‘restless leg syndrome’ is common.
Secondary changes include pes cavus, scoliosis, and hammer toe. Cardiac disease is frequently present and heart failure is the most common cause of death. Most patients have hypertrophic cardiomyopathy with characteristic EKG changes and some have subaortic stenosis as part of the hypertrophied myocardium. Diabetes mellitus is present in 20-25%. Some hearing loss occurs in more than 10% of individuals.
Most patients require a wheelchair within 15 years of disease onset and the mean age of death is about 36 years.
Rare patients with a later onset of FRDA retain lower limb deep tendon reflexes.