Absence of clinically relevant growth acceleration in untreated children with non-classical congenital adrenal hyperplasia

Background/Aims: In classical congenital adrenal hyperplasia (CAH), elevation of adrenal androgens leads to accelerated growth and bone maturation with compromised adult height. In untreated children with non-classical CAH (NC-CAH), in which adrenal androgens are generally only slightly increased, growth velocity may not be significantly elevated. Methods: Twenty-four patients were included and divided into a symptomatic and an asymptomatic group. Height was expressed as height standard deviation scores (HSDS) and corrected for target height (HSDS-THSDS). Bone maturation was expressed as bone age acceleration (BA _c = bone age - calendar age). Linear mixed models with random factor patient were used for the analysis of growth and bone age. Results: In symptomatic patients (n = 17), HSDS-THSDS only slightly increased by 0.06 SDS per year (95% CI 0.02-0.10). Mean BA _c was 2.21 years (SDS 0.66, p < 0.0001). In asymptomatic patients (n = 7), no significant growth acceleration or BA _c was found. Conclusions: In untreated NC-CAH children, growth acceleration is small and generally not visible on their growth charts. BA _c is more pronounced. Therefore, the absence of an increase in growth velocity does not exclude the diagnosis of NC-CAH. When considering this diagnosis, bone age acceleration should also be taken into account.