kiranmayi
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Two sisters are diagnosed with hemolytic anemia. Their older brother was previously diagnosed with the same disorder. Two other brothers are asymptomatic. The mother and father are second cousins. Deficiency of which of the following enzymes would be most likely to cause this disorder?
A. Debranching enzyme
B. Glucose-6-phosphatase
C. Glucose-6-phosphate dehydrogenase
D. Muscle phosphorylase
E. Pyruvate kinase
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| asmi
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C ?
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| kiranmayi
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The correct answer is E. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is inherited as an X-linked recessive trait, so females would not be affected. Pyruvate kinase is a glycolytic enzyme; pyruvate kinase deficiency is an autosomal recessive disorder, affecting males and females approximately equally. If this enzyme is deficient, red cells have trouble producing enough ATP to maintain the Na+/K+ pump on the plasma membrane, secondarily causing swelling and lysis.
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| asmi
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thanks kiran
That was a good question
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| usmleasr
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:idea:
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| asmi
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and these people will have right shift of O2 dissociation curve because of elevated 2,3 BPG secondary to defect in RBC'S anerobic glycolysis .
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