To date, 34 missense variants have been reported in HGMD leading to four distinct syndromes: PRPS1 superactivity (OMIM#300661), X-linked Charcot-Marie-Tooth disease-5 (CMTX5: OMIM#311070), Arts syndrome (OMIM#301835), and isolated X-linked sensorineural deafness (DFNX1: OMIM#304500). This evidence concerns the gene PRPS1 and Lethal ataxia with deafness and optic atrophy.