Newborn screening-detected 21-hydroxylase deficiency: growth pattern is not associated with the genotype.

Background: Normalizing growth in children with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (21OHD-CAH) requires a long-term maintenance of a fragile balance between hydrocortisone (HC) replacement and androgen suppression. The growth pattern in children with 21OHD-CAH diagnosed by clinical symptoms has been evaluated in numerous retrospective studies. The aim of this study was to evaluate growth of patients with 21OHD-CAH detected by newborn screening (NBS), prior to clinical symptoms.

Methods: Nation-wide NBS for 21OHD-CAH was implemented in the Czech Republic in 2006. Since then, 1,317,987 neonates were screened (2006-2017) and 21OHD-CAH was confirmed in 108 patients. Growth was evaluated as height-standard deviation score (SDS) at regular time-points, related to bone age and compared to recent population standards. In 88 patients, available data allowed long-term evaluation of growth, HC and fludrocortisone doses (in half-year intervals), with a median observation period of ten years.

Results: Body height in affected children was shorter between years 1-9 of life with a nadir at age 1-3 years. Their height did not differ from general population at the age 10-12 years. There were not found differences according to 21OHD-CAH severity.

Conclusions: NBS is an effective secondary prevention tool for the early detection of 21OHD-CAH which improves growth patterns. A significant growth deceleration was observed during infancy and early childhood periods but with following height normalization. Growth pattern was not associated with the genotype of 21OHD, if patients have been detected by NBS.