Non-Classical Congenital Adrenal Hyperplasia-Causing Alleles in Adolescent Girls with PCOS and in Risk Group for PCOS Development

Background: Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women. Depending on the diagnostic criteria applied, it occurs in up to 16.6% of the general female population. Congenital adrenal hyperplasia includes a group of autosomal recessive disorders, the most common of which is non-classical congenital adrenal hyperplasia (NCAH) caused by mutations in the CYP21A2 gene. PCOS and NCAH have similar clinical manifestations (hyperandrogenemia, i.e., hirsutism, acne, alopecia, and increased androgen levels in the blood) and potential impact on long-term health (infertility, increased risk of type 2 diabetes, and cardiovascular disease. Consequently, it is thought that NCAH mutations in the heterozygous state may play a role in PCOS development and phenotypic expression.

Objective: To determine the prevalence of the most common pathogenic alleles of the CYP21A2 gene in adolescents with PCOS and adolescents at risk of PCOS development, and to compare the results with healthy adolescents matched for gynecological age.

Methods: A cross-sectional study was conducted with 55 PCOS patients, 23 risk patients (with hyperandrogenism but a normal menstrual cycle), and 49 healthy adolescents. Genetic variations in the CYP21A2 gene were analyzed using a standard Multiplex Ligation-dependent Probe Amplification test (SALSA MLPA Probemix P050-C1 CAH; MRC Holland).

Results: No significant differences were found among the three groups regarding the frequency of carriers of NCAH variations in the heterozygous state. It was found that the I172N carrier in the PCOS group had a significantly higher Global Acne Grading Scale score than PCOS patients without this variation (p = 0.038). Within the control group of healthy adolescents, compound heterozygous carriers (IVS2-12A > G and -113G > A) had a significantly higher body mass index than non-carriers (p = 0.036).

Conclusion: We found no differences in the incidence of NCAH-causing variations in the heterozygous state in adolescent PCOS patients, risk adolescents (with hirsutism but normal menstruation), and healthy adolescents. Future studies of larger cohorts and rarer pathogenic CYP21A2 gene variations are required.