ESPE Abstracts

Introduction: Early identification of classic 21OH-Congenital Adrenal Hyperplasia (21OH-CAH) through newborn screening (NBS) is crucial to prevent adrenal crises, especially in males. Today 21 OH-CAH NBS is performed in 5/21 regions of Italy. This study aims to report the results of 21OH-CAH NBS in Italy from 2006 to 2019.

Methods: All patients underwent a dried blood spot (DBS) test for 17OH-progesterone (17OHP) within the first 48-72 hours of life. According to different regional protocols, for the preterm newborns, different thresholds for 17OHP and specific protocols for retesting were utilized, mainly based on gestational ages or birth weight. In 1/5 region of Italy, the second-tier test with Tandem Mass MS/MS was utilized from 2018. The analysis included the number of newborns screened, the sensitivity of NBS for SW-CAH, the number of positive cases, the recall rate (RR) and predictive positive value (PPV), the number of false negatives (FN), age at blood sampling, number of cases suspected before NBS results.

Results: A total of 2,933,074 newborns were screened, and 166 pts (78M,88F) were diagnosed with classic 21OH-CAH, resulting in an incidence rate of 1:17,669 newborns. The Salt Wasting (SW) CAH was the most common form identified (125 pts, 80%), with 100% of NBS sensitivity. The mean age at blood sampling in true positive cases was 9±18 days of life. In 46/166 (28%) cases, the diagnosis was suspected before the NBS

Results: in 35 females due to genital ambiguity, in another 4 females, and in 7 males due to prenatal diagnosis. Overall, the mean RR was 0.77; the mean PPV was 1.02. Three FN cases (2M) with simple virilizing 21OH-CAH were diagnosed in infancy. In the region where 2nd tier was available, the recall rate in the last 2 years was 0.17, with a PPV of 4.3.

Discussion: The results of this study demonstrate the effectiveness of newborn screening for the early detection of SW 21OH-CAH. The mean age at blood sampling suggests that timely reporting of screening results is crucial to ensure early diagnosis and treatment. The recall rate and PPV could be dramatically improved by implementing 2nd tier-test protocols. The data analyzed in this study provide valuable insights into the epidemiology of CAH and may provide useful information to guide Italian public health interventions aimed at improving the health outcomes of infants with CAH.