Molecular genetic study of congenital adrenal hyperplasia in Serbia: novel p.Leu129Pro and p.Ser165Pro CYP21A2 gene mutations

Purpose Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease characterized by impaired adrenal steroidogenesis and most often caused by CYP21A2 gene mutations. For the first time, we reported complete spectrum and frequency of CYP21A2 gene mutations in 61 unrelated patients with classical and non-classical CAH from Serbia. Methods Direct DNA sequencing of whole CYP21A2 gene and polymerase chain reaction with sequence-specific primers for detection of CYP21A1P/CYP21A2 chimeras were combined. Results We identified 18 different pathogenic alleles-two of them novel. Mutation detection rate was highest in patients with salt-wasting form of CAH (94.7 %). The most prevalent mutation was intron 2 splice site mutation, c.290-13A/C > G (18.5 %). Other mutation frequencies were: CYP21A1P/CYP21A2 chimeras (13 %), p.P30L (13 %), p.R356W (11.1 %), p.G110fs (7.4 %), p.Q318X (4.6 %), p.V281L (4.6 %), p.I172N (2.8 %), p.L307fs (2.8 %), p.P453S (1.9 %), etc. Mainly, frequencies were similar to those in Slavic populations and bordering countries. However, we found 6.5 % of alleles with multiple mutations, frequently including p.P453S. Effects of novel mutations, c.386T > C (p.Leu129Pro) and c.493T > C (p.Ser165Pro), were characterized in silico as deleterious. The effect of well-known mutations on Serbian patients' phenotype was as expected. Conclusions The first comprehensive molecular genetic study of Serbian CAH patients revealed two novel CYP21A2 mutations. This study will enable genetic counseling in our population and contribute to better understanding of molecular landscape of CAH in Europe.