OdG1

Disorders of sex development (DSD) are conditions where genetic, gonadal, and/or internal/external genital sexes are discordant. In many cases, serum testosterone determination is insufficient for the differential diagnosis. Anti-Müllerian hormone (AMH), a glycoprotein hormone produced in large amounts by immature testicular Sertoli cells, may be an extremely helpful parameter. In undervirilized 46,XY DSD, AMH is low in gonadal dysgenesis while it is normal or high in androgen insensitivity and androgen synthesis defects. Virilization of a 46,XX newborn indicates androgen action during fetal development, either from testicular tissue or from the adrenals or placenta. Recognizing congenital adrenal hyperplasia is usually quite easy, but other conditions may be more difficult to identify. In 46,XX newborns, serum AMH measurement can easily detect the existence of testicular tissue, leading to the diagnosis of ovotesticular DSD. In sex chromosomal DSD, where the gonads are more or less dysgenetic, AMH levels are indicative of the amount of functioning testicular tissue. Finally, in boys with a persistent Müllerian duct syndrome, undetectable or very low serum AMH suggests a mutation of the AMH gene, whereas normal AMH levels orient toward a mutation of the AMH receptor.

Purpose of review: This review focuses on the pathogenesis, diagnosis, management and long-term outcomes of disorders of sex development, specifically women with Swyer syndrome (46,XY complete gonadal dysgenesis). Recent findings: Recent discoveries have broadened our understanding of the complex pathways involved in normal and abnormal sex development. In 46,XY gonadal dysgenesis, lack of testis development may be triggered by sex determining region Y, NR5A1, DHH or testis-determining gene loss-of-function mutations, DAX1 or WNT4 duplication or MAP3K1 gain-of-function mutations. The diagnosis and management of patients with Swyer syndrome is complex, and optimal care requires an experienced multidisciplinary team. Early diagnosis is vital because of the significant risk of germ cell tumour, and bilateral gonadectomy should be performed. Furthermore, early sex hormone treatment is necessary to induce and maintain typical pubertal development and to achieve optimal bone mineral accumulation. Pregnancy is possible via ova donation, and outcomes are similar to women with 46,XX ovarian failure. Summary: Further pathogenic gene mutations are likely to be identified, and the function, interaction and phenotypic effects of new and existing mutations will be further defined. Patients require long-term follow-up in specialist centres.

In this review, the elements included in both sex determination and sex differentiation are briefly analyzed, exposing the pathophysiological and clinical classification of disorders or anomalies of sex development. Anomalies in sex determination without sex ambiguity include gonadal dysgenesis, polysomies, male XX, and Klinefelter syndrome (dysgenesis and polysomies with a female phenotype; and sex reversal and Klinefelter with a male phenotype). Other infertility situations could also be included here as minor degrees of dysgenesis. Anomalies in sex determination with sex ambiguity should (usually) include testicular dysgenesis and ovotesticular disorders. Among the anomalies in sex differentiation, we include: (1) males with androgen deficiency (MAD) that correspond to those individuals whose karyotype and gonads are male (XY and testes), but the phenotype can be female due to different hormonal abnormalities. (2) females with androgen excess (FAE); these patients have ovaries and a 46,XX karyotype, but present varying degrees of external genital virilization as a result of an enzyme abnormality that affects adrenal steroid biosynthesis and leads to congenital adrenal hyperplasia; less frequently, this can be caused by iatrogenia or tumors. (3) Kallman syndrome. All of these anomalies are reviewed and analyzed herein, as well as related fertility problems.