[Differential diagnosis and treatment of girls with 46XY-karyotype and androgen insensitivity syndrome].

The importance of the secretion and action of androgens during the critical period of male sexual development is exemplified in patients with androgen insensitivity syndrome. Their karyotype is always 46XY. In 2 sisters, aged 11 and 13 years, the androgen insensitivity syndrome was diagnosed based on an androgen receptor gene mutation. Ambiguous genital development of a new-born was shown to be due to a lack of testosterone production, based on a luteinizing hormone receptor gene mutation. Finally, in a phenotypically female new-born a gene mutation of 17-beta hydroxysteroid dehydrogenase type 3 was found to be responsible for insufficient testosterone synthesis during embryonic development. The presentation of a patient, and specifically a neonate, with abnormal genital development represents a difficult diagnostic and therapeutic challenge. Referral to a centre with experience in the diagnosis and management of disorders of sexual development is advised where the emphasis should be on psychological and genetic counselling.