Abstract
BACKGROUND: Adrenocortical hyperplasia is an autosomal recessive disorder characterized by congenital metabolic dysfunction, resulting in endocrine disturbances and abnormal sexual development (such as female masculinity), requiring lifelong hormonal therapy. Notably, non-classical congenital adrenal hyperplasia (NCCAH) exhibits clinical manifestations resembling polycystic ovary syndrome (PCOS), yet their therapeutic approaches in fertility treatment differ substantially. Importantly, NCCAH carries the risk of delivering offspring with severe adrenal hyperplasia, which presents far graver consequences than PCOS. Accurate differentiation between these two conditions is therefore crucial for proper clinical management. However, to date, no large-scale screening studies have been conducted to investigate the prevalence and carrier status of NCCAH among PCOS populations. METHODS: A total of 1,372 suspected PCOS patients were genotyped by long-read sequencing in this study. To further clarify phenotypic characteristics, detailed clinical evaluation and laboratory analysis were conducted on 947 of these patients. RESULTS: The prevalence of NCCAH in suspected PCOS patients was 0.73‰ (95% CIs: 0.02-4.05‰; 1/1,372). The carrier rate for the CAH variants in PCOS patients was 4.45% (61/1,371, 95% CIs: 3.42-5.68%), of which 78.69% were CYP21A2 variants. The carrier frequencies for classic CAH and NCCAH in PCOS patients were 1.46% (95% CIs: 0.89-2.24%) and 2.04% (95% CIs: 1.36-2.94%), respectively. PCOS patients with hirsutism exhibited a significantly higher NCCAH carrier rate compared to those without hirsutism (3.90% vs. 0.37%, p<0.001). However, other clinical features such as irregular menstrual cycles, insulin resistance, and obesity showed no correlation with CAH carrier status. No significant differences in clinical or paraclinical characteristics were found among CAH carriers. CONCLUSIONS: PCOS patients had similar CAH carrier rates with the general population in China, and carriers of CAH variants are generally asymptomatic.