<prompt> Lesh Nyhan syndrome is due to deficiency of :HGPRTaseCPS ICPS IIPRPP synthetase  <response>: Ans-ARef: Harpers Illustrated Biochemistry 29th edition. Page no: 335, 339 742.Explanation:Lesh-Nyhan Syndrome :A bizarre syndrome characterizes by hyperuricemia. urolithiasis and self-mutilation.Enzyme defect:Hypoxanthine-guanine Phosphoribosyl Transferase HGPRTase.This enzyme is involved in purine salvage it converts hypoxanthine to inosine monophosphate IMP.In absence of this enzyme, intracellular PRPP levels will be elevated.Mutation in the gene producing HGPRTase may be due to deletion, frameshift mutation, base substitutions or abberent m RNA splicing.Note: Salvage reactions require less energy than the De novo synthesis. 