Auchus and Arlt believe that an A4/T ratio greater than 0.5 is an indicator of significant adrenal contribution to the total T level in males with CAH and if the A4/T ratio is greater than 1 with concomitant LH suppression then the majority of the circulating T is of adrenal origin (17, 18). This evidence concerns the gene PLOD1 and congenital adrenal hyperplasia.