Friedreich's ataxia (also known as FRDA or FA; OMIM229300) is the most prevalent inherited ataxia in humans, with a population frequency of 1-2:50,000 (Campuzano et al., 1996), and is caused by deficient levels of the mitochondrial protein frataxin (encoded by FXN) (Campuzano et al., 1997). The gene discussed is FXN; the disease is Friedreich ataxia.