Störungen der geschlechtsdifferenzierung durch defekte der steroidbiosynthese

The biosynthesis of sex steroids is dependent on a normal development of both adrenals and gonads. Both disorders of organ development as well as defects of specific enzyme action may hinder normal sexual development of an individual. Androgenic steroids determine development of the sexual phenotype, because they induce virilisation of the external genitalia. Mostly in some forms of congenital adrenal hyperplasia, excess androgen formation will lead to genital ambiguity up to a male phenotype in patients with female karyotype. On the other hand, diminished androgen action can be the cause for defective or absent virilisation in karyotypic males. This may be caused by combined adrenal and gonadal insufficient steroid synthesis with the clinical signs of congenital adrenal hyperplasia or due to isolated defects of testicular androgen biosynthesis. For diagnosis, hormone analysis often with prior stimulatory tests has to be performed. The molecular basis for enzyme defects of sex steroid biosynthesis has been elucidated and direct molecular genetic analysis may be feasible in individual cases. However, the phenotype of these disorders is highly variable which cannot be explained in detail nowadays. Therapy includes supplementation of gluco- and mineralocorticoids in cases of congenital adrenal hyperplasia. The therapeutic use of androgenic steroids in cases of a severe virilisation deficit has not been implemented in general. Genital ambiguity is surgically corrected on an individual basis.