Question
Primary hyperoxaluria is caused by defective metabolism of:
A. Alanine
B. Arginine
C. Glycine
D. All of the above
Show Answer
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Correct Answer » C
Explanation
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Ans:C
-In nonketotic hyperglycinemia, a rare inborn error of glycine degradation presently known only in Finland, glycine accumulates in all body tissues including the central nervous system.
-The main defect in primary hyperoxaluria type I is the deficiency of the alanine glyoxalate aminotransferase in liver peroxisomes causing failure to catabolize glyoxylate formed by the deamination of glycine.
-Subsequent oxidation of glyoxylate to oxalate results in urolithiasis, nephrocalcinosis, and early mortality from renal failure or hypertension. Glycinuria results from a defect in renal tubular reabsorption.
