Androgen insensitivity syndrome
Updates to Article Attributes
Androgen insensitivity syndrome (AIS), also known as testicular feminisation syndrome, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings.
Epidemiology
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.
Clinical presentation
Patients can often present with primary amenorrhoea.
Pathology
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 a blind-ending vagina.
Genetics
Thought to carry an X-linked recessive inheritance 3 where multiple mutations in the androgen receptor (AR(AR) gene have been localised to the long arm of the X chromosome (i.e. Xq11-13).
Subtypes
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
Radiographic features
General imaging features include:
bilateral cryptorchidism +/- juxta-testicular Müllerian duct cysts
absent/rudimentary uterus
shortened vagina
Ultrasound
Usually, the first modality to locate the testes, and document absent uterus.
MRI
The modality of choice to accurately delineate Müllerianüllerian duct anomalies, and localise testes. It may also diagnose testicular malignancy, if any, in cryptorchid testes 7.
Treatment and prognosis
These patients have an increased incidence of malignancy in the undescended testes:
Differential diagnosis
Mayer-Rokitansky-Küsterüster-Hauser syndrome has female karyotype with normal female genitalia, and ovaries, but the uterus is rudimentary or absent 7.
See also
-<p><strong>Androgen insensitivity syndrome (AIS)</strong>, also known as <strong>testicular feminisation syndrome</strong>, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings. </p><p>Epidemiology</p><p>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.</p><p>Clinical presentation</p><p>Patients can often present with <a href="/articles/primary-amenorrhoea">primary amenorrhoea</a>.</p><p>Pathology</p><p>Affected individuals are genotypically male with a 46XY karyotype but with a female phenotype (<a href="/articles/male-pseudohermaphroditism">male pseudohermaphroditism</a>). Individuals often have bilateral <a href="/articles/cryptorchidism">cryptorchidism</a>. The undescended testes often produce oestradiol. There may be a blind-ending vagina. </p><p>Genetics</p><p>Thought to carry an X-linked recessive inheritance <sup>3</sup> where multiple mutations in the androgen receptor (AR) gene have been localised to the long arm of the X chromosome (i.e. Xq11-13).</p><p>Subtypes</p><p>Although it is a disease spectrum it may be subtyped according to the extent of severity as:</p><ul>- +<p><strong>Androgen insensitivity syndrome (AIS)</strong>, also known as <strong>testicular feminisation syndrome</strong>, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings. </p><h4>Epidemiology</h4><p>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.</p><h4>Clinical presentation</h4><p>Patients can often present with <a href="/articles/primary-amenorrhoea">primary amenorrhoea</a>.</p><h4>Pathology</h4><p>Affected individuals are genotypically male with a 46XY karyotype but with a female phenotype (<a href="/articles/male-pseudohermaphroditism">male pseudohermaphroditism</a>). Individuals often have bilateral <a href="/articles/cryptorchidism">cryptorchidism</a>. The undescended testes often produce oestradiol. There may be a blind-ending vagina. </p><h5>Genetics</h5><p>Thought to carry an X-linked recessive inheritance <sup>3</sup> where multiple mutations in the androgen receptor (<em>AR</em>) gene have been localised to the long arm of the X chromosome (i.e. Xq11-13).</p><h5>Subtypes</h5><p>Although it is a disease spectrum it may be subtyped according to the extent of severity as:</p><ul>
-</ul><p>Radiographic features</p><p>General imaging features include:</p><ul>- +</ul><h4>Radiographic features</h4><p>General imaging features include:</p><ul>
-</ul><p>Ultrasound</p><p>Usually, the first modality to locate the testes, and document absent uterus.</p><p>MRI</p><p>The modality of choice to accurately delineate <a href="/articles/mullerian-duct-anomalies">M</a><a href="/articles/mullerian-duct-anomalies">ü</a><a href="/articles/mullerian-duct-anomalies">llerian duct anomalies</a>, and localise testes. It may also diagnose testicular malignancy, if any, in cryptorchid testes <sup>7</sup>.</p><p>Treatment and prognosis </p><p>These patients have an increased incidence of malignancy in the undescended testes:</p><ul>- +</ul><h5>Ultrasound</h5><p>Usually, the first modality to locate the testes, and document absent uterus.</p><h5>MRI</h5><p>The modality of choice to accurately delineate <a href="/articles/mullerian-duct-anomalies">Müllerian duct anomalies</a>, and localise testes. It may also diagnose testicular malignancy, if any, in cryptorchid testes <sup>7</sup>.</p><h4>Treatment and prognosis</h4><p>These patients have an increased incidence of malignancy in the undescended testes:</p><ul>
-</ul><p>Differential diagnosis</p><p><a href="/articles/mayer-rokitansky-kuster-hauser-syndrome">Mayer-Rokitansky-K</a><a href="/articles/mayer-rokitansky-kuster-hauser-syndrome">ü</a><a href="/articles/mayer-rokitansky-kuster-hauser-syndrome">ster-Hauser syndrome</a> has female karyotype with normal female genitalia, and ovaries, but the uterus is rudimentary or absent <sup>7</sup>.</p><p>See also</p><ul><li><p><a href="/articles/disorders-of-gender-development">disorders of gender development</a></p></li></ul>- +</ul><h4>Differential diagnosis</h4><p><a href="/articles/mayer-rokitansky-kuster-hauser-syndrome">Mayer-Rokitansky-Küster-Hauser syndrome</a> has female karyotype with normal female genitalia, and ovaries, but the uterus is rudimentary or absent <sup>7</sup>.</p><h4>See also</h4><ul><li><p><a href="/articles/disorders-of-gender-development">disorders of gender development</a></p></li></ul>
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