Pathogenicity of Congenital Adrenal Hyperplasia Induced by the p.P377L Mutation of CYP11B1

CYP11B1 encodes an 11β-hydroxylase that is involved in the catalysis of adrenal glucocorticoids and the production of cortisol. Mutations in CYP11B1 can result in congenital adrenal hyperplasia. We discovered a proband with a CYP11B1 gene mutation. Gene sequencing revealed a homozygous missense mutation of c.1130C > T in the 7th exon of the CYP11B1 gene that resulted in the change from Pro377 to leucine in the encoded protein. Based on the proband's clinical symptoms and the prognosis according to the database, this mutation may be harmful. However, the pathogenicity has not yet been reported. Thus, we created an expression vector for the mutation in vitro, transfected cells, observed the changes in gene expression, and determined its pathogenicity. To determine the pathogenicity of the CYP11B1 p.P377L mutation site through in vitro verification. The eukaryotic expression vector of the CYP11B1 mutation site was constructed in vitro, and the success of the construct was confirmed by sequencing. Fluorescence microscopy was used to determine the transfection effectiveness, GFP fluorescent tag labeling was used to detect changes in protein localization, and qRT‒PCR and Western blotting were used to detect CYP11B1 mRNA and protein expression. Sequencing revealed that the proband harbored a homozygous missense mutation of CYP11B1 (p.P377L). The expression of the protein decreased but the localization did not change when cells were transfected with the CYP11B1 mutation vector compared to the wild-type vector. The p.P377L mutation of CYP11B1 could affect protein expression and enzymatic activity and may be pathogenic.