Abstract:

Objective

To analyze the relationship between the genetic mutations and clinical parameters in 21-hydroxylase deficiency (21-OHD) patients and their pedigrees.

Methods

Sixteen 21-OHD patients from Shanghai Children' s Medical Center and their parents were enrolled from December 2011 to May 2013. Genomic DNA was extracted from the peripheral blood sample. All the 10 exons of CYP21A2 gene were amplified by PCR using specific primers and directly sequenced to detect disease-causing mutations.

Results

Analysis of the 16 patients revealed 6 kinds of mutations in CYP21A2 gene. The most frequent mutations of CYP21A2 gene were IVS2-13A/C>G [50%(16/32)] and p.I172N [25%(8/32)], while the c.1451_1452delinsC[3%(1/32)] and p. R149P [3%(1/32)] were rare mutations. All these gene variations detected in the patients were also identified in the parent samples, except for the two cases with incomplete pedigree. The most frequent molecular defect of the salt-wasting form and simple virilizing form was IVS2-13A/C>G [75%(15/20)] and p.I172N [67%(8/12)] respectively. Correlation between genotypes and phenotypes was compatible with the reported data.

Conclusion

The method in this study based on the directly sequencing can identify mutations on CYP21A2 gene with high specificity, which provided a reliable method for molecular diagnosis of 21-OHD.

Key words: 21-Hydroxylase deficiency, Cytochrome P450, Gene