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  #1  
Old 07-22-2012
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Biochemistry Dehydration and Ambiguous Genitalia; Which Enzyme?

The mother of a 3-month-old infant girl has noticed that her daughter is continually thirsty. Physical examination of the infant shows sunken fontanelles and poor skin turgor indicating dehydration. The external genitalia are ambiguous. Laboratory studies show an elevated urine sodium level, hypocortisolism, and an increased level of plasma corticotropin. A chromosome study shows an XX genotype. Which of the following enzymes is most likely deficient in this patient?

a) 17α-Hydroxylase
b) 18-Hydroxylase
c) 21-Hydroxylase
d) 5α-Reductase
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Old 07-22-2012
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Would be C
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Old 07-22-2012
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21-hydroxylase with mineralocorticoid deficiency, hypocortisolism and virilisation
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Old 07-22-2012
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yup C would be my answer too
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Old 07-23-2012
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Default correct answer :)

yup, correct answer is c) 21-Hydroxylase

The patient has adrenogenital syndrome caused by hypocortisolism. 21-Hydroxylase deficiency leads to decreased cortisol (increased corticotropin) and aldosterone (sodium loss and volume depletion).
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