Prevalence of congenital adrenal hyperplasia among sudden infant death in the Czech Republic and Austria.

This study aimed to estimate the number of infants who died of unrecognized congenital adrenal hyperplasia (CAH) in Austria and the Czech Republic within the past 13 years, before the introduction of adequate neonatal screening. The study was based on retrospective analysis of neonatal screening cards of 242 infants who died suddenly between 7 days and 12 months of age and whose cause of death could not be identified. 17-hydroxyprogesterone (17-OHP) was measured by fluoroimmunoassay and positive samples were subsequently genotyped. Three infants out of 242 may have had unrecognized CAH due to CYP21 (steroid 21-hydroxylase) gene defect. Their newborn 17-OHP levels and CYP21 genotypes were 706 nmol/l and del/conv//del/conv, 53 nmol/l and I2//I2, and 811 nmol/l and I2//Gln318stop, respectively. CAH due to CYP21 defect can lead to sudden unexpected death without prior symptoms typical for the condition. Hence, newborn screening would have prevented these deaths had it been available. In addition, we have shown that the I2 point mutation that is expected to lead to simple virilizing form may lead to a fatal outcome.