,3 Although CYP21A2 genotyping of infants and parents has been shown to be clinically useful in the care of infants with confirmed CAH or clinically suspected SW-CAH,17, 18, 19, 20 the utility of genotyping as a second-tier NBS test for infants with elevated 17OHP screening results has not been demonstrated,3,15,17 In addition, it is important to consider the balance of costs and benefits of routine CYP21A2 genotyping given limited public health resources. This evidence concerns the gene CYP21A2 and congenital adrenal hyperplasia.