Question

In 100 words or less, explain why a loss-of-function mutation in 11β-hydroxylase causes growth of the adrenal cortex in the human fetus. Include in your answer an statement of which hormones you would measure in this child to convince yourself that there is loss of 11β-hydroxylase activity?

Answer 1

11beta hydroxylase is the enzyme required for conversion of 11-Deoxycortisol into cortisol and also for conversion of deoxycorticosterone into corticosterone which finally gives aldosterone. Loss of function mutation in this enzyme leads to decreased synthesis of cortisol and aldosterone which stimulates ACTH synthesis and causes accumulation of steroid precursors and therefore causes congenital adrenal hyperplasia(growth of adrenal cortex) . Loss of 11 beta hydroxylase activity can be diagnosed by measuring the levels of steroid precursors mainly 17-hydroxyprogesterone and also by measuring testosterone levels.(whose levels are increased in this condition)