[Clinical, hormonal and molecular genetic characteristics of patients with 46,XY disorders of sex development associated with variants in the gene].

BACKGROUND

Deficiency of 17β-hydroxysteroid dehydrogenase type 3 (HSD17B3) is a rare variant of 46,XY disorders of sex development (DSD).

AIM

To give clinical, hormonal and molecular genetic characteristics of cases of 46,XY DSD associated with variants in the HSD17B3 gene.

MATERIALS AND METHODS

The study included 310 patients with 46,XY DSD for the period from 2015 to 2019. The patients underwent a comprehensive examination, including a study of the steroid profile by high-performance liquid chromatography with tandem mass spectrometric detection, as well as a molecular genetic analysis using NGS.

RESULTS

According to the results of molecular genetic studies, biallelic nucleotide substitutions in the HSD17B3 gene were detected in 13 cases, which accounted for 4.2% of the total number of patients with 46,XY DSD. All 13 patients with biallelic variants in the HSD17B3 gene were registered as females. The ratio of androstenedione/testosterone concentrations in the blood in this group ranged from 1.4 to 8.9. 2 variants in the HSD17B3 gene were found in several patients: c.277+4A>T (on 6 chromosomes) and c.729_735del:p.V243fs (on 9 chromosomes). 4 novel variants have been identified. Monoallelic nucleotide substitutions in the HSD17B3 gene were detected in 7 cases, which accounted for 2.3% of the total number of patients with 46,XY DSD. External genitalia in this group corresponded to Prader stages 3-4. In 1 patient, a pathogenic variant c.277+4A>T was detected in the HSD17B3 gene, in other cases variants with uncertain significance were detected.

CONCLUSION

In the structure of 46,XY DSD, patients with biallelic variants in the HSD17B3 gene were identified in 4.2% of cases, with monoallelic variants - in 2.3% of cases. 4 novel variants were found in the HSD17B3 gene.