Neonatal Screening for Congenital Adrenal Hyperplasia in Guangzhou: 7 Years of Experience

Area of Science:

• Endocrinology
• Genetics
• Neonatal Screening

Background:

• Congenital adrenal hyperplasia (CAH) is a group of genetic disorders affecting the adrenal glands.
• Neonatal screening is crucial for early detection and management of CAH, particularly the classical forms.
• The 21-hydroxylase deficiency is the most common cause of CAH, leading to hormonal imbalances.

Purpose of the Study:

• To evaluate the effectiveness of the neonatal screening program for congenital adrenal hyperplasia (CAH) in Guangzhou, China.
• To determine the incidence and clinical forms of CAH in the screened population.
• To assess the impact of gestational age and sample collection time on 17-hydroxyprogesterone (17-OHP) levels and optimize screening protocols.

Main Methods:

• Screening of 818,417 newborns for CAH using 17-hydroxyprogesterone (17-OHP) levels in dried blood spots.
• Stratified cut-off values based on gestational age (GA) and sample collection timing.
• Confirmatory testing including biochemical analyses, Sanger sequencing, and multiplex ligation-dependent probe amplification of the *CYP21A2* gene for positive cases.

Main Results:

• A total of 40 patients with classical 21-hydroxylase deficiency were identified between 2018 and 2024.
• The overall incidence of CAH was 1 in 20,653 (95% CI: 1:34,928–1:14,661).
• The salt-wasting form accounted for 70% (28 cases) and the simple virilizing form for 30% (12 cases). No significant differences in prevalence were found between sexes or preterm/full-term infants.

Conclusions:

• Neonatal CAH screening in Guangzhou identified a significant number of classical cases.
• The incidence of CAH in this population is comparable to other regions.
• Implementing multitiered cut-off values adjusted for GA and collection time can enhance screening efficiency for CAH.