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.