A capillary electrophoresis-based assay for carrier screening of the hotspot mutations in the CYP21A2 gene

Molecular genetic analysis of the cytochrome P450 family 21 subfamily A member 2 (<i>CYP21A2</i>) gene is challenging owing to the highly homologous with its pseudogene. A reliable approach for the large-scale population screening of <i>CYP21A2</i> is required. This study aimed to establish and evaluate a capillary electrophoresis-based assay for hotspot mutation carrier screening of the <i>CYP21A2</i> gene. A total of 22 different variants in the <i>CYP21A2</i> gene were detected by a capillary electrophoresis-based assay consisting of single nucleotide primer extension (SNaPshot) and high-throughput ligation-dependent probe amplification (HLPA) in the Chinese population, and the results were validated by alternative methods. Among the 5376 subjects, 1.51 % (81/5376) individuals were identified as <i>CYP21A2</i> pathogenic variant carriers, with a carrier rate of 1/66. A total of 11 different variants were identified, of which c.293-13A/C > G (33.33 %) was the most common variant, followed by c.844C > T (19.75 %), c.518T > A (19.75 %), and Del/Con (16.05 %). There was a 100 % concordance between capillary electrophoresis and alternative method results. Furthermore, a total of 63 individuals (1.17 %, 63/5376) carried the c.955C > T (p. Q319∗) variant, among which 61 (61/63, 96.83 %) had a duplicated <i>CYP21A2</i> gene and are therefore not carriers of a <i>CYP21A2</i> allele. In conclusion, the capillary electrophoresis-based assay is an accurate and effective approach for genotyping the <i>CYP21A2</i> gene and has the potential for the large-scale population screening of <i>CYP21A2</i>.