<prompt> Lesch-Nyhan syndrome, the sex linked recessive disorder is due to the lack of the enzyme:Hypoxanthine-guanine phosphoribosyl transferaseXanthine oxidaseAdenine phosphoribosyl transferaseAdenosine deaminase  <response>: Ans. A. Hypoxanthine-guanine phosphoribosyl transferasePurine biosynthesis takes place by de novo and salvage pathway. Erythrocytes, Neutrophils and the brain cells lack the enzyme PRPP-amido transferase so salvage pathway is operative there. It is one step synthesis.HGPRT ase Hypoxanthine guanine phosphoribosyl transferaseDeficiency of HGPRT Hypoxanthine-guanine phosphoribosyl transferase leads to an inherited X-linked disorder, Lesch- Nyhan syndrome, which affects only males. In this salvage pathway is not operative, purines cant be converted into nucleotides and degraded to uric acid. The symptoms area. Hyperuricemiab. Goutc. Urinary tract stonesd. Neurological symptoms of mental retardatione. Self-mutilation painful, destructive biting of fingers and lips. 