Complete androgen insensitivity syndrome: a rare case of disorder of sex development

Genetic control of typical and atypical sex development

Sex development relies on the sex-specific action of gene networks to differentiate the bipotential gonads of the growing fetus into testis or ovaries, followed by the differentiation of internal and external genitalia depending on the presence or absence of hormones. Differences in sex development (DSD) arise from congenital alterations during any of these processes, and are classified depending on sex chromosomal constitution as sex chromosome DSD, 46,XY DSD or 46,XX DSD. Understanding the genetics and embryology of typical and atypical sex development is essential for diagnosing, treating and managing DSD. Advances have been made in understanding the genetic causes of DSD over the past 10 years, especially for 46,XY DSD. Additional information is required to better understand ovarian and female development and to identify further genetic causes of 46,XX DSD, besides congenital adrenal hyperplasia. Ongoing research is focused on the discovery of further genes related to typical and atypical sex development and, therefore, on improving diagnosis of DSD.

Testicular Feminization or Androgen Insensitivity Syndrome (AIS) in Iran: a Retrospective Analysis of 30-Year Data

BACKGROUND

Androgen insensitivity syndrome (AIS) or testicular feminization is a partial or complete inability of cell response to androgen. The cause is enzymatic defect in synthesis of testosterone, resulting sexually immature phenotypically female, with primary amenorrhea. There are three categories of AIS, complete, partial and mild, depending on the degree of external genital masculinization. The aim of this study was to find out chromosomal abnormalities, and correlation between AIS and maternal/paternal age, parents' consanguineous marriage, family history and clinical observation, in Iranian AIS patients.

METHOD

This study includes a retrospective data analysis of 72,000 families' medical records in the Genetic Clinic in Tehran, during a 30-yr period (1984-2014). The essential basis for the patients' referral to the clinic by gynecologists was primary amenorrhea. Cytogenetic abnormalities has been confirmed by chromosome G-banding and conventional staining methods.

RESULTS

Seventy AIS female patients with 46XY pattern were cytogenetically diagnosed and the frequency of AIS syndrome was estimated about 0.05% (∼70/140000). The results showed no association between AIS and maternal or paternal age nor were the marital pattern of the parents. The clinical findings illustrated that primary amenorrhea had the highest indication for referral of AIS patients for genetic counseling and cytogenetic study.

CONCLUSION

No correlation was observed between AIS and maternal or paternal age or consanguineous marriages. Amenorrhea is the most clinically observed sign of AIS patients.

Androgen receptor (AR) physiological roles in male and female reproductive systems: lessons learned from AR-knockout mice lacking AR in selective cells

Androgens/androgen receptor (AR) signaling is involved primarily in the development of male-specific phenotypes during embryogenesis, spermatogenesis, sexual behavior, and fertility during adult life. However, this signaling has also been shown to play an important role in development of female reproductive organs and their functions, such as ovarian folliculogenesis, embryonic implantation, and uterine and breast development. The establishment of the testicular feminization (Tfm) mouse model exploiting the X-linked Tfm mutation in mice has been a good in vivo tool for studying the human complete androgen insensitivity syndrome, but this mouse may not be the perfect in vivo model. Mouse models with various cell-specific AR knockout (ARKO) might allow us to study AR roles in individual types of cells in these male and female reproductive systems, although discrepancies are found in results between labs, probably due to using various Cre mice and/or knocking out AR in different AR domains. Nevertheless, no doubt exists that the continuous development of these ARKO mouse models and careful studies will provide information useful for understanding AR roles in reproductive systems of humans and may help us to develop more effective and more specific therapeutic approaches for reproductive system-related diseases.