What kinds of errors can affect purine and pyrimidine

Purines and pyrimidines play crucial roles in cellular energy systems signaling and in the production of DNA and RNA. Purines and pyrimidines can either be synthesized de novo or from normal catabolism, via a salvage pathway. Uric acid is the end product of the purine catabolism, and Citric Acid cycle intermediates are the products of pyrimidine catabolism.

question:
* What happens when there are errors in the metabolism of purines and/or pyrimidines?
* How is the body affected?
* What kinds of errors can affect purine and pyrimidine metabolism? How do these errors affect these two processes?