This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2018, Subject name: Biochemistry
The enzyme deficient in Lysch Nyhan syndrome is:- 
Select and explain. 
A. Adenosine Deaminase, B. PRPP synthetase, C. HGPase, D. Xanthine oxidase
C: HGPase
Answer: C: HGPase 
Explanation: HGPase (Hypoxanthine guanine phosphoribosyl transferase) deficiency: Causes Lesch-Nyhan syndrome. | synthesis of purine nucleotides |utilization of purines (hypoxanthine and guanine) by salvage pathway-accumulation of PRPP (Neurotoxic component)- Self mutilation Defect in salvage pathway- | IMP and CMP - impairment feedback regulation of their production