Structure-based activity prediction of CYP21A2 stability variants: A survey of available gene variations

Abstract

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency accounts for 90–95% of CAH cases. In this work we performed an extensive survey of mutations and SNPs modifying the coding sequence of the CYP21A2 gene. Using bioinformatic tools and two plausible CYP21A2 structures as templates, we initially classified all known mutants (n = 343) according to their putative functional impacts, which were either reported in the literature or inferred from structural models. We then performed a detailed analysis on the subset of mutations believed to exclusively impact protein stability. For those mutants, the predicted stability was calculated and correlated with the variant’s expected activity. A high concordance was obtained when comparing our predictions with available in vitro residual activities and/or the patient’s phenotype. The predicted stability and derived activity of all reported mutations and SNPs lacking functional assays (n = 108) were assessed. As expected, most of the SNPs (52/76) showed no biological implications. Moreover, this approach was applied to evaluate the putative synergy that could emerge when two mutations occurred in cis. In addition, we propose a putative pathogenic effect of five novel mutations, p.L107Q, p.L122R, p.R132H, p.P335L and p.H466fs, found in 21-hydroxylase deficient patients of our cohort.

A Case of Salt-Wasting Congenital Adrenal Hyperplasia with Triple Homozygous Mutation: Review of Literature

“…The fact is that the mutations were all in homozygous condition and never been reported previously. The R369Q mutation consists of arginine/glutamine substitution in position 1106 (c.1106G > A), 11 probably, this mutation is less relevant than other mutations for the phenotype of the present case, since it is generally associated with nonclassical CAH. 12 The other two mutations are referred to as "gene conversion mutations," although the underlying mechanism has not been fully clarified.…”

Genetic characterization of a large cohort of Argentine 21‐hydroxylase Deficiency

“…We found 35 rare or novel variants among the 343 sequenced samples (60 nonrelated alleles: 24 (14.5%) alleles from classical patients and 36 (7.2%) from NC, Table S1). We had previously reported 12 of these rare genetic variants 20,21,23,27 . In this study, we found three additional novel variants: p.(S166F) (GenBank ID: MH310941), p.(P189R) (GenBank ID: MH310942) and p.(R436L) (GenBank ID: MH310943) (see Table S2 for a summary of the clinical description of the patients).…”

“…CYP21A2 p.(S166F), p.(P189R), p.(G264R) and p.(R436L) variants were classified and evaluated as previously described 27 using PDB ID: 4Y8W 28 with progesterone and PDB ID: 5VBU with 17‐hydroxyprogesterone 29 as the human 21‐hydroxylase templates. UCSF Chimera program was used for structural visualization 30 and Adobe Photoshop CC 2019 program (http://www.adobe.com) for the compilation of the images.…”

Congenital Adrenal Hyperplasia

“…8 Yet, despite the large number of reported mutations, approximately 10 mutations account for the majority of affected alleles. Most mutations result from gene conversion events.…”