A Case of 11[beta]-Hydroxylase Deficiency Detected in a Newborn Screening Program by Second-Tier LC-MS/MS

Background/Aim: 21-Hydroxylase deficiency congenital adrenal hyperplasia (CAH) is one of the target diseases in many newborn screening programs. 11β-Hydroxylase defiency is less frequent and does not cause salt-losing crisis. Thus, it is not a target disease for newborn screening. However, affected newborns might show slightly elevated levels of 17-OH-progesterone (17-OHP) in the standard immunoassay screening test. The objective is to show that the diagnosis of 11β-hydroxylase deficiency can be done using a dried blood spot from newborn screening. Case Report: A male newborn was born at term. Blood sample for newborn screening was taken 36 h after birth. 17-OHP was slightly elevated using time-resolved fluorescence immunoassay (72.8 nmol/l; cut-off