Androgen insensitivity syndrome

Androgen insensitivity syndrome (AIS), also known as the testicular feminisation syndrome, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings. 

The incidence may vary dependent on whether it is complete or incomplete. Rough estimated incidence rates is ~1 in 20,000 to 50,000 live births.

Patients can often present with primary amenorrhoea.

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 oestradiol. There may be blind ending vagina. 

Genetics

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).

Subtypes

Although it is a disease spectrum it may be sub typed according to the extend of severity as:

General imaging features include

Ultrasound

Usually, the first modality to locate the testes, and document absent uterus.

MRI

Modality of choice to accurately delineate mullerian duct anomalies, and localize testes. It may also diagnose testicular malignancy, if any, in cryptorchid testes 7.

Mayer-Rokitansky-Kuster-Hauser syndrome have female karyotype with normal female genitalia, and ovaries, however uterus is rudimentary or absent 7.

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Article Information

rID: 13865
Section: Syndromes
Tag: cases
Synonyms or Alternate Spellings:
  • Testicular feminisation syndrome
  • Androgen insensitivity syndrome (AIS)
  • Testicular feminisation syndrome (TFS)
  • Testicular feminization syndrome
  • Testicular feminization syndrome (TFS)

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