For examples, an autosomal recessively-inherited GAA trinucleotide repeat expansions in FXN, encoding frataxin, cause Friedrich’s ataxia, which is characterized by progressive ataxia, impaired speech, loss of vibratory and proprioceptive sensation due to degeneration of spinal cord neurons and nerve fiber tracts connecting to the cerebellum. Here, FXN is linked to cerebellar ataxia.