Objective: To explore the genotype-phenotype correlation among 18 patients with 21-hydroxylase deficiency (21-OHD).
Methods: PCR-Sanger sequencing was used to analyze the 10 exons and flanking regions of the CYP21A2 gene among the 18 patients and 20 healthy controls.
Results: Seventeen patients had variants of the CYP21A2 gene. Eight patients (44.4%, 8/18) carried homozygous variants including p.Ile 173Asn (62.5%, 5/8), p.Pro31Leu (25.0%, 2/8), and IVS2-13A/C>G (12.5%, 1/8), respectively. Six patients (33.3%, 6/18) carried compound heterozygous variant, among which IVS2-13 A>G+p.Ile 173Asn were most common (50.0%). 94.4% (34/36) of the variant were pathogenic, with the most common variants being p.Ile173Asn (41.7%), IVS2-13A/C>G (19.4%), and p.Ile173Asn (7.5%). No variant was identified among the 20 healthy controls.
Conclusion: The majority of 21-OHD patients carried CYP21A2 gene variants in homozygous or compound heterozygous forms, among which the p.Ile173Asn was the most common one. There is a strong correlation between the genotypes and clinical phenotypes.