Early diagnosis of 5alpha-reductase deficiency in newborns.

Abstract

5Alpha-reductase-2 deficiency is a rare autosomal recessive form of 46,XY disorders of sex differentiation (DSD), caused by mutations in the steroid 5alpha-reductase type 2 gene (SRD5A2), presenting at birth with variable degrees of undervirilization. We report on three Italian newborns with 46,XY DSD in whom the evaluation of testosterone, dihydrotestosterone, testosterone/dihydrotestosterone (T/DHT) ratio and molecular analysis of the 5alpha-reductase type 2 gene was made in their first month of life. Baseline T/DHT ratio suggested 5alpha-reductase-2 deficiency; the diagnosis was confirmed by molecular genetics (homozygous mutation in exon 4 [G196S], heterozygous mutation in exon 1 and 5 [W35X/Y235F], heterozygous mutation plus polymorphism in exon 1 [G34W/A49T]). Proper investigation permitted early reassignment to male sex in two babies, assigned to female sex just after birth. In infancy, the T/DHT ratio, assessed by suitable assay methods and evaluated by age-appropriate reference values, seems to be able to select newborns affected by 5alpha-reductase-2 deficiency. Molecular analysis of the SRD5A2 gene should be warranted in newborns with abnormal ratio before sex assignment.

• Authors: S Bertelloni, R T Scaramuzzo, D Parrini, F Baldinotti, S Tumini, P Ghirri
• Journal: Sexual development : genetics, molecular biology, evolution, endocrinology, embryology, and pathology of sex determination and differentiation (Sex Dev) Vol. 1 Issue 3 Pg. 147-51 ( 2007) ISSN: 1661-5433 [Electronic] Switzerland
• PMID: 18391525 (Publication Type: Journal Article)
• Copyright: 2007 S. Karger AG, Basel

Chemical References

• 3-Oxo-5-alpha-Steroid 4-Dehydrogenase
• steroid-5alpha-reductase type 2

Topics

• 3-Oxo-5-alpha-Steroid 4-Dehydrogenase (deficiency)
• Disorders of Sex Development (diagnosis, enzymology)
• Female
• Humans
• Infant, Newborn
• Male