Molecular Mechanisms of 17β-Hydroxysteroid Dehydrogenase Deficiency

17β-HSD3 deficiency arises from loss-of-function mutations in the HSD17B3 gene, which encodes the enzyme responsible for the final reduction of androstenedione to testosterone in the fetal testis. Disruption of this step in the canonical steroidogenic pathway leads to undervirilisation in 46,XY individuals, with phenotypes ranging from female-appearing external genitalia at birth to partial virilisation at puberty via extragonadal steroid conversion. At the molecular level, missense and splice-site mutations can destabilise the Rossmann-fold coenzyme-binding domain, perturb the catalytic tetrad or induce exon skipping, yielding truncated or inactive proteins. Structural studies pinpoint how substitution of key residues within the active site impairs substrate orientation and hydride transfer. Concurrently, compensatory upregulation of alternative 17β-HSD isoforms in peripheral tissues modulates androgen exposure postnatally. Advances in enzyme kinetics, molecular modelling and cellular expression assays have clarified genotype–phenotype correlations, informing early diagnostic strategies, hormone-replacement protocols and personalised therapeutic interventions.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Molecular Mechanisms of 17β-Hydroxysteroid Dehydrogenase Deficiency publication trend

The graph below shows the total number of articles in molecular mechanisms of 17β-hydroxysteroid dehydrogenase deficiency across all publications each year (not limited to Nature Index journals).

Technical terms

17β-Hydroxysteroid Dehydrogenase Type 3 (17β-HSD3): Enzyme in fetal testes that catalyses the reduction of androstenedione to testosterone.

Androstenedione: Steroid precursor converted to testosterone by 17β-HSD3.

Missense mutation: Single-base substitution in DNA resulting in an altered amino acid in the protein.

Splice-site mutation: Genetic alteration at intron–exon junctions that disrupts normal RNA splicing.

Catalytic tetrad: Quartet of conserved amino acids within an enzyme active site essential for its catalytic mechanism.

References

1. Disorder of Sex Development Due to 17-Beta-Hydroxysteroid Dehydrogenase Type 3 Deficiency: A Case Report and Review of 70 Different HSD17B3 Mutations Reported in 239 Patients. International Journal of Molecular Sciences (2022).
2. Molecular mechanisms underlying the defects of two novel mutations in the HSD17B3 gene found in the Tunisian population. The Journal of Steroid Biochemistry and Molecular Biology (2022).
3. Analyses of Molecular Characteristics and Enzymatic Activities of Ovine HSD17B3. Animals (2021).