A novel homozygous mutation IVS6+5G>T in CYP11B1 gene in a Vietnamese patient with 11β-hydroxylase deficiency

• We report a case showing typical symptoms of CAH.
• A novel mutation IV+5G>T was detected in the CYP11B1 gene of Vietnamese patient.
• This mutant could affect the gene splicing during transcription.
• Mutation IVS6+5G>T might be explained the phenotype of patient.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease which is characterized by a deficiency of one of the enzymes involved in the synthesis of cortisol from cholesterol by the adrenal cortex. CAH cases arising from impaired 11β-hydroxylase are the second most common form. Mutations in the CYP11B1 gene are the cause of 11β-hydroxylase deficiency. This study was performed on a patient with congenital adrenal hyperplasia and with premature development such as enlarged penis, muscle development, high blood pressure, and bone age equivalent of 5 years old at 2 years of chronological age. Biochemical tests for steroids confirmed the diagnosis of CAH. We used PCR and sequencing to screen for mutations in CYP11B1 gene. Results showed that the patient has a novel homozygous mutation of guanine (G) to thymine (T) in intron 6 (IVS6+5G>T). The analysis of this mutation by MaxEntScan boundary software indicated that this mutant could affect the gene splicing during transcription.