Androgen insensitivity syndrome
Citation, DOI & article data
Androgen insensitivity syndrome (AIS), also known as the testicular feminization syndrome, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings.
The incidence may vary depending on whether it is complete or incomplete. Roughly estimated incidence rates are ~1 in 20,000 to 50,000 live births.
Patients can often present with primary amenorrhea.
Affected individuals are genotypically male with a 46XY karyotype but with a female phenotype (male pseudohermaphroditism). Individuals often have bilateral cryptorchidism. The undescended testes often produce estradiol. There may be a blind-ending vagina.
Thought to carry an X linked recessive inheritance 3 where multiple mutations in the androgen receptor (AR) gene has been localized to the long arm of the X chromosome (i.e. Xq11-13).
Although it is a disease spectrum it may be subtyped according to the extent of severity as:
- complete androgen insensitivity syndrome (CAIS): Morris syndrome
- incomplete: partial androgen insensitivity syndrome / Reifenstein syndrome
General imaging features include:
- bilateral cryptorchidism +/- juxta-testicular Müllerian duct cysts
- absent/rudimentary uterus
- shortened vagina
Usually, the first modality to locate the testes, and document absent uterus.
Treatment and prognosis
These patients have an increased incidence of malignancy in the undescended testes:
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