What enzyme deficiency is most closely associated with the symptoms of Lesch-Nyhan syndrome?

• A. ој-Aminolevulinate synthase
• B. Hypoxanthine-guanine phosphoribosyl transferase
• C. Xanthine oxidase
• D. Glycine-oxaloacetic transaminase

Answer: (B)

Lesch-Nyhan syndrome is primarily associated with a deficiency of the enzyme hypoxanthine-guanine phosphoribosyl transferase (HGPRT). This enzyme plays a crucial role in the purine salvage pathway, which allows for the recycling of purines back into nucleotides. When this enzyme is deficient, there is an accumulation of uric acid due to increased de novo synthesis of purines as well as a decreased ability to salvage them. The resultant overproduction of uric acid can lead to symptoms such as gout and neurological issues, which are characteristic of Lesch-Nyhan syndrome.

Additionally, the neurological manifestations include self-harm behaviors and motor dysfunction, which further emphasize the impact of this enzyme's deficiency on brain metabolism and function. The specific functional loss linked to HGPRT deficiency clearly highlights its important role, further establishing the connection between this genetic disorder and the enzyme in question.