Prevalence, clinical characteristics and long-term outcomes of classical 11 β-hydroxylase deficiency (11BOHD) in Turkish population and novel mutations in CYP11B1 gene.
CYP11B1 mutations are known to be race-specific and are concentrated in exons 3 and 8, of which mutations in the former are mostly associated with non-classical 11OHD, whereas mutations in the latter are mostly found in classical 11OHD, characterized by severe loss of enzymatic activity.
11β-Hydroxylase deficiency (11OHD) is a common form of congenital adrenal hyperplasia that has been shown to result from inactivating CYP11B1 mutations, and pathogenic CYP11B2/CYP11B1 chimeras contribute to a minority of cases.
Further analysis of variants in other hypertension-related genes, steroid synthesis and metabolism compensatory pathways, and/or the investigation of chimeric CYP11B genes are needed to clarify the phenotypic heterogeneity in 11β-hydroxylase deficiency.
With an estimated prevalence of 1 in 100 000 births, 11β-hydroxylase deficiency is the second most common form of congenital adrenal hyperplasia (CAH) and is caused by mutations in CYP11B1 Clinical features include virilization, early gonadotropin-independent precocious puberty, hypertension, and reduced stature.
In conclusion, this study expands the spectrum of mutations in CYP11B1 causing to 11β-OHD and provides evidence for prenatal diagnosis and genetic counseling.
In summary, CAH due to steroid 11β-hydroxylase deficiency can be attributed to both the novel deletion mutation (g.9525_9526delCT, corresponding to p.L380V…R420X) and known missense mutation (g.5194G>C corresponding to p.D63H) in CYP11B1.
We performed molecular genetic analysis of the CYP11B1 gene in six patients with preliminary clinical diagnosis of 11β-OHD and four patients identified as potential 11β-OHD from a CAH cohort in which CYP21A2 gene mutations consecutively screened.
We hypothesize that the lack expression of CYP11B1 under the control of the CYP11B2 promoter in zona fasciculata may contribute to a cortisol defect as well as the resultant 11-OHD.
In order to clarify the underlying mechanism causing 11β-OHD, we performed the molecular genetic analysis of the CYP11B1 gene in a female patient diagnosed as classical 11β-OHD.
The molecular genetic analysis was performed by direct nucleotide sequencing of the CYP11B1 gene in 15 unrelated Tunisian patients suffering from classical 11β-hydroxylase deficiency.