Phosphoribosyl pyrophosphate synthetase (PRS) I deficiency is a rare medical condition caused by missense variants in PRPS1 that lead to four different phenotypes: Arts Syndrome (MIM 301835), X‐linked Charcot‐Marie‐Tooth (CMTX5, MIM 311070), X‐linked non‐syndromic sensorineural deafness (DFNX1, MIM 304500), and Phosphoribosylpyrophosphate Synthetase Superactivity (MIM 300661). Here, PRPS1 is linked to Lethal ataxia with deafness and optic atrophy.