Novel homozygous p.Y395X mutation in the CYP11B1 gene found in a Vietnamese patient with 11β-hydroxylase deficiency.

CONTEXT: The deficiency of steroid 11β-hydroxylase is caused by mutations in the CYP11B1 gene and is the second major form of congenital adrenal hyperplasia associated with hypertension.

OBJECTIVE

The objective of this study was to screen the CYP11B1 gene for mutations in one Vietnamese male suffering from congenital adrenal hyperplasia.

PATIENT: The patient (46,XY) had congenital adrenal hyperplasia. The clinical manifestations presented precocious puberty, hyper-pigmentation and high blood pressure at 4 years.

RESULTS

The patient was a homozygous carrier of a novel mutation located in exon 7 containing a premature stop codon instead of tyrosine at 395 (p.Y395X).

CONCLUSION

We have identified a novel mutant of the CYP11B1 gene in one Vietnamese family associated with phenotypes of congenital adrenal hyperplasia. The mutant gene p.Y395X produces a truncated form of the polypeptide and abolishes the enzyme activities, leading to a severe phenotype of congenital adrenal hyperplasia.