Objective: The most common form of congenital adrenal hyperplasia (CAH) is the deficiency of steroid 21-hydroxylase which results from deletion or mutation of the cytochrome P450 21-hydroxylase gene. The low level of glucocorticoids and in some cases low level of mineralocorticoids has an important pathophysiological influence on the axis of the hypothalamo-pituitary-adrenal cortex.
Design: Using determination of plasmatic metanephrine, normetanephrine and chromogranin A, we wanted to investigate the structure and function of adrenal medulla in patients with CAH, because adrenocortical and adrenomedullary systems are intimately linked anatomically and functionally.
Methods: Levels of plasmatic metanephrine, normetanephrine and chromogranin A were measured in our group of 37 patients (age range: 5-45 years, 18 females and 19 males) with the classic salt-wasting form of CAH.
Results: The reference range was 73% for metanephrine (<10 ng/L, 83.3% females, 63.2% males) and 59.5% for metanephrine (<15 ng/L, 72.2% females, 47.4% males). The concentration of plasmatic nephrines in the first quartile reference range was achieved in the case of metanephrine in all patients (<23 ng/L), and in the case of normetanephrine in 86.5% of patients (<42.5 ng/L). The level in chromogranin A was normal in all patients. No significant differences were found in plasmatic concentrations of nephrines and chromogranin A between males and females with CAH, nor was there a significant correlation with genetic results (severe or moderate salt-wasting form of CAH).
Conclusion: Impaired secretion of glucocorticoids in patients with CAH leads to the structural changes in adrenal medulla which are expressed by low production of metanephrine, and to a lesser extent, normetanephrine.