Comprehensive Genetic Analysis and Structural Characterization of CYP21A2 Mutations in CAH Patients.

Carvalho B, Pereira M, Marques CJ, Carvalho D, Leão M, Oliveira JP, Barros A, Carvalho F.

Source

Department of Genetics, Faculty of Medicine, University of Porto, Porto, Portugal.

Abstract

Congenital Adrenal Hyperplasia (CAH) due to 21-hydroxylase deficiency is a common autosomal recessive disorder caused by mutations in the steroid 21-hydroxylase gene (CYP21A2). Complete DNA sequencing of CYP21A2 was performed in 5 patients, 3 non-classic and 2 classic forms of the disease, that were previously screened for the 10 most common mutations, in order to detect additional mutations that could justify the phenotype of the patients. 5 mutations were identified with the whole gene extended analysis. The mutations, p.Pro432Leu and p.Ala434Glu, the first previously reported by our group and the second a novel one were structurally analyzed with ICM-Pro software regarding biochemical properties such as protein stability, accessibility to surface and hydrophobicity, in order to elucidate their effects on the CYP21A2 protein. The 2 affected residues, Pro432 and Ala434, were also studied for conservation purposes in order to predict the severity of both mutations with PolyPhen-2 software and were considered as "probably damaging". Prediction of clinical severity, based on molecular modelling and sequence conservation, was in accordance with the patient's clinical diagnosis.
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