[Correlation between variants of CYP21A2 gene promoter region and nonclassical 21-hydroxylase deficiency].

Objective: To summarize the clinical characteristics of two children with nonclassical 21 hydroxylase deficiency (NC-21OHD) due to variants of CYP21A2 gene promoter region.
Methods: Clinical characteristics and the results of genetic testing were reviewed.
Results: The main clinical manifestations of the two children included precocious puberty with poor bone age/progression control and menstrual disorder with hirsutism. Patient 1 had compound heterozygous variants for -126C>T, -113G>A, -110T>C and p.I173N; her mother was heterozygous for -126C>T, -113G>A and -110T>C, and her father was heterozygous for p.I173N. Patient 2 had compound heterozygous variants for -126C>T, -113G>A and p.I2G, whose mother was heterozygous for -126C>T and -113G>A, and father was heterozygous for p.I2G.
Conclusion: Diagnosis of NC-21OHD should be considered for children with hirsutism, menstrual disorder and poor bone age/progression control. The promoter region of CYP21A2 gene should be analyzed when no variant is detected in its coding regions.