Friedreich's Ataxia


Friedreich's ataxia (FRDA) which represents out 1/2 of all cases of hereditary ataxia has a prevalence of 2-4/100,000 and is the most common form of hereditary ataxia. The classic form has an age of onset between 2-25 years, and about 25% have an atypical presentation with milder phenotype and onset after 25 years. Typically, gait unsteadiness begins in childhood often simultaneous with spinal scoliosis. Gait ataxia progresses steadily, but worsening of both ataxia and scoliosis may seem greater during rapid growth in puberty. Dysarthria and hand incoordination usually develop in the next few years. Gait unsteadiness is particularly poor in darkness, due to prominent involvement of posterior columns. Optic nerve atrophy occurs in approximately 25% and sensorineural hearing loss in 10% of FRDA patients. Progression of the ataxia in the classic form is fairly uniform and patients are wheelchair bound 12 years after onset. Death may occur from the mid-thirties to the sixth and seventh decades, particularly with the milder variants (see below). Death is often related to cardiomyopathy, diabetes, or aspiration pneumonia. There is as yet no definitive treatment for FRDA, and management chiefly involves supportive care and avoidance of complications. As in all patients with ataxia, physical therapy and rest combine to allow patients to cope with increasing disability. Dysphagia and aspiration should be minimized. Spasticity may be managed with baclofen. Spinal scoliosis or kyphoscoliosis is present in over 90% of patients and may appear before the onset of imbalance. Intervention with bracing or surgical placement of stabilizing rods may be necessary to avoid deformities that reduce mobility and pulmonary function. Ten to twenty percent of patients with FRDA develop diabetes mellitus, an average of 15 years after onset of ataxic symptoms.