NucleotideSynthesisMetabolism

Question 1

Nucleotide Synthesis and Metabolism

Defects in Pyrimidine Metabolism - Hereditary Orotic Aciduria

Answer 1

with a deficiency of OROTATE PHOSPHORIBOSYLTRANSFERASE; there is accumulation of orotic acid in the blood and urine and failure to thrive; treatment= administer uracil or uridine and they get converted in to a nucleotide

Question 2

Nucleotide Synthesis and Metabolism

Defects in Pyrmidine and Purine Metabolism - Adenosine deaminase deficiency

Answer 2

deficiency of ADENOSINE DEAMINASE causes SCID (severe combined immunodeficiency); treated by putting children in bubble environment; Treated by adenosine deaminase injections, genetic engineering involving intro of adenosine deaminase gene by viral vector (problems could occur with this if it gets into a tumor suppressor genes to make leukemia)

Question 3

Nucleotide Synthesis and Metabolism

Defects in Pyrmidine and Purine Metabolism - Lesch-Nyhan Syndrome

Answer 3

deficiency of HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE (HGPT) - salvage enzyme; causes hyperuricemia (get increase in uric acid, which is sparingly soluble), mental retardation and self mutilation(have appreciation for it) . Uric Acid increases, higer risk of crystallizing out in joints (gout) and kidney stones. Normal catabolic pathway of purine = Hypoxanthine–>xanthine–>Uric Acid; with this defect you have less salvage of hypoxanthine and therefore there is much more available to go to uric acid and since you are normally already at max solubility, then it crystalizes out

Question 4

Nucleotide Synthesis and Metabolism

Defects in Pyrmidine and Purine Metabolism - Gout

Answer 4

abnormalities of purine metabolizing enzymes may result in elevated levels of uric acid resulting in painful deposition of uric acid in joints; Big toe = most pain; elevation of uric acid; sometimes over production of purines and uric acid dietary component; aggrevated by foods with high purine nucleotides –“disease of the rich”