Nucleotide Degradation

Question 1

What is Lesch Nyhan syndrome caused by?

Answer 1

A deficiency in HGPRT activity because of mutations in the gene; it is very rare; cannot salvage purines efficiently, so de novo synthesis increases; PRPP levels increase because less is consumed through salvage pathway and IMP and GMP levels drop; this provides more substrates for Gln-PRPP AT, and less inhibition because of lacking end product; therefore high rates of de novo synthesis; this, combined with decreased utilization of purines, will lead to elevated levels of uric acid production

Question 2

What is gout caused by?

Answer 2

High blood levels of uric acid due to overproduction or under excretion of uric acid
Crystals of uric acid deposit in joints causing pain and inflammation