21-Hydroxylase and 11β-Hydroxylase Mutations in Romanian Patients with Classic Congenital Adrenal Hyperplasia

Abstract

CONTEXT: Congenital adrenal hyperplasia (CAH) comprises autosomal recessive disorders mainly due to defects in the 21-hydroxylase (CYP21) gene. OBJECTIVE: The study aimed to perform molecular characterization in 43 Romanian patients with classical CAH forms diagnosed at the Center for Genetic Diseases of the Pediatric Clinic/University Cluj (38 with 21-hydroxylase deficiency, five with 11beta-hydroxylase deficiency), to determine the frequency of mutations in the CYP21A2 gene and attempt a genotype-phenotype correlation in patients with 21-hydroxylase deficiency. DESIGN: Molecular analysis was performed by direct sequencing of PCR amplified products of the CYP21A2 and CYP11B1 genes. RESULTS: The most frequent mutation in Romanian patients with 21-hydroxylase deficiency was I2G (43.9%), followed by deletions and large conversions (16.7%), I172N and the triple mutation (P30L+I2G+del8bp), accounting for 12.1% each, P30L (7.6%) and R356W (1.5%). Genotypes were categorized in three mutation groups (0, A, and B), according to their predicted functional consequences, and compared with clinical phenotype. Positive predictive values were 100, 75, and 100% for groups 0, A, and B, respectively. Overall genotype-phenotype correlation was 87.88%. In the five patients with 11beta-hydroxylase deficiency, the following homozygous mutations were identified: T318R in two related patients; R448H in two unrelated patients; and P94L, a new, yet-undescribed mutation. CONCLUSION: The present study is the first countrywide report of mutational analysis in a Romanian patient population with 21-hydroxylase deficiency. Molecular diagnosis was performed in a small number of CAH patients proved not to suffer from 21-hydroxylase deficiency but from 11beta-hydroxylase deficiency, and a new mutation was identified.