PRPS1 and Lethal ataxia with deafness and optic atrophy: Mutations in PRPS1 are normally found in the more severe Arts syndrome, Charcot-Marie Tooth, and nonsyndromic sensorineural deafness, so if mutations in this gene had only been identified in one family, this may have been disregarded as the pathogenic cause of disease (Fiorentino et al., 2018).