Late Onset of symptoms in Friedreich Ataxia

Onset of symptoms is typically after 20 years (range 20-60yrs; loss of coordination, ataxia). Progression is slower progression requiring assistance with ambulation; use of walker, scooter 10-15 years after diagnosis. Some individuals present with increased muscle tone, rigidity and spasticity. Retained reflexes has been observed in some. Dysarthria is less severe. MRI studies show cerebellar vermian atrophy in about 50% of individuals. Cardiomyopathy is rare. Individuals with gait and limb ataxias, dysarthria, loss of vibration sense, and fixational instability after age 25 years should be considered for molecular testing for GAA expansion in the FXN gene (late-onset patient typically has shorter GAA repeat on at least one allele; shortest observed in symptomatic individual ~65 repeats).