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During normal screening for phenylketonuria, a male newborn has a serum phenylalanine concentration of 35 mg/dl (greater than 20 mg/dl is considered a +ve test). Signs of tyrosine deficiency are also apparent. Enzymatic analysis using cultured fibroblasts, obtained after circumcision, show normal activity of phenylalanine hydroxylase. A possible explanation for these findings is a deficiency in function of which of the following coenzymes?
A. Adenosylcobalamin
B. Biopterin
C. Dihydroquinone
D. Pyridoxal phosphate
E. Tetrahydrofolic acid
explain plz
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is it c?? i come to it by exclusion
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B. Phenyalanie hydroxylase needs trtrahydrobiopterin (BH4) as the cofactor
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got this from wiki
Classical PKU is caused by a defective gene for the enzyme phenylalanine hydroxylase (PAH), which converts the amino acid phenylalanine to other essential compounds in the body. A rarer form of the disease occurs when PAH is normal but there is a defect in the biosynthesis or recycling of the cofactor tetrahydrobiopterin (BH4) by the patient. This cofactor is necessary for proper activity of the enzyme. Other, non-PAH mutations can also cause PKU
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a patient of yours has galactose 1 phosphate uridyl transferase deficiency. What enzyme is missing? What is the clinical presentation? What is the treatment?
A) This dx is the most common error of carbohydrate metabolism, galactosemia. Glycolysis is affected, and you see evidence of liver failure, direct hyperbilirubinemia, coag disorders, renal problems (acidosis, glycosuria), emesis, and sepsis. TREAT by eliminating all formulas and foods with galactose.
Q) What is the enzyme disease associated with ornithine transcarbamylase deficiency? How is it inherited? What toxic metabolite forms? MOA? Clinical presentation? Treatment?
A) This...OTCD...is a urea cycle defect inherited in an X-linked fashion. Ornithine couples with carbamylphosphate to make citrulline. If the enzyme is def., ornithine builds up and then urea cannot be made and excreted. AMMONIA builds up instead, and within only 24 hours, the newborn baby will become lethargic and have seizures. DIAGNOSIS by measuring the orotic acid levels in the urine. TREAT with a low fat diet and alternate pathways to excrete nitrogen via benzoic acid and phenylacetate.
