Schwere 46,XY virilisierungsstörung durch 17β-hydroxysteroid dehydrogenase 3 mangel

Background: 17β hydroxysteroid dehydrogenase deficiency is a presumable rare cause for a severe virilization disorder in children with 46,XY karyotype due to a defect in the testicular testosterone biosynthesis from androstenedione. Patient: We report on a 14 year old child with 46,XY karyotype with a predominantly female phenotype. Results: Hormonal analysis showed low values for androstenedione and testosterone before and after stimulation with human chorionic gonadotropin, however, the androstenedione/testosterone ratio was elevated. Molecular genetic analysis proved the diagnosis of 17β-hydroxysteroid dehydrogenase deficiency due to a homozygous mutation (325+4 A-T) in the HSD17B3-gene, which leads to an aberrant splicing process. Conclusions: This case demonstrates that in addition to a meticulous steroid analysis a direct molecular genetic analysis can be helpful in the diagnosis of 17β-hydroxysteroid dehydrogenase deficiency.