Abstract: Abstract: Objective To investigate the clinical and molecular genetic characteristics of a Chinese patient with 21-hydrosylase deficiency (21-OHD). Methods Clinical features and laboratory data were collected from that patient. Ten exons and the boundaries of exon-intron of CYP21A2 gene were amplified by PCR and sequenced. The correlation between clinical characteristics and genotype was analyzed. Results The female patient was diagnosed as 21-OHD with simple-virilizing form according to the clinical manifestation. DNA sequencing results showed a heterozygous mutation. One allele of the patient contained a base transversion (T>A) at c.515 and led to a missense mutation of Ile to Asn at the 172th amino acid. The other allele had one base transversion (T>G) at c.593 and led to a nonsense mutation at the 198th codon, which is a new mutation. The novel compound heterozygous mutations cause the simple-virilizing form of congenital adrenal hyperplasia. Conclusion Through CYP21A2 gene analysis, a new mutation causing 21-OHD was found, which broadened the mutation database, and the clinical diagnosis of 21-OHD was confirmed.

Key words: 21-hydrosylase deficiency, CYP21A2 gene, gene mutions