What is the metabolic defect in Lesch-Nyhan syndrome resulting in intellectual disability and self-mutilation tendencies?

Lesch-Nyhan syndrome is caused by a specific metabolic defect related to the purine salvage pathway, primarily involving the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). In this condition, the defect in salvaging guanine and hypoxanthine leads to an excessive buildup of uric acid, which is responsible for several clinical manifestations, including gout-like symptoms, neurological issues, and behavioral problems such as self-mutilation tendencies.

In individuals with Lesch-Nyhan syndrome, the inability to effectively recycle purines results in intellectual disability and the hallmark behaviors seen in this syndrome. The excess uric acid can lead to nephrolithiasis (kidney stones) and a range of other complications due to high levels of uric acid in the body.

This understanding of the purine metabolism and the specific enzyme deficiency helps clarify how Lesch-Nyhan syndrome leads to its characteristic features. The other options pertain to different metabolic pathways and do not accurately describe the underlying defect responsible for the symptoms observed in Lesch-Nyhan syndrome.