Endocrine Abstracts

Introduction: In medical practice ambiguous genitalia is a relatively are condition. The combination of two causes in genital malformation is exceptional. Our aim is to describe a person having an abnormal karyotype with a chimerism (46,XY/46,XX) and a deficit in 17β-hydroxysteroid dehydrogenase 3 (17β-HSD): an enzyme in the testes that transforms D4 Androstenedione to testosterone and androstenedione to dihydro testosterone or DHT.

Case report: X aged 21, whose parents are cousins, educated as a girl, came for primary amenorrhea. Clinical examination showed deep voice, mild ambiguous genitalia, clitoro-megaly and two testes (one in the scrotum and the second highly situated). The breast was Tanner’s stage 1, body hair repartition looks like a woman’s. Hormonal assessment showed high testosterone for a woman and low for a man (9.25 nmol/l) and very high D4A (13 ng/ml). On ultrasound female structures were absent. Pelvis MRI confirmed both testes and seminal vesicules. The karyotype showed a mosaic: 46,XY (96%) and 46,XX (5%) or chimerism.

Conclusion: In our case, the male pseudo hermaphrodism is apparently due to the combination of two exceptional abnormalities. The first one is a chimerism in which the person has the male chromosomal complement (XY), but some cells have the female chromosomal complement (XX). The second is also a very rare as partial deficit in 17β-HSD3, i.e. enzyme that transforms D4A to testosterone and androsterone to DHT. Both exceptional situations can lead to ambiguous genitalia.