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Androgen insensitivity syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Androgen Insensitivity Syndrome

Androgen insensitivity syndrome is a genetic condition in which the body’s cells cannot respond to male sex hormones (androgens), resulting in a spectrum of sexual development outcomes.

Overview

Androgen insensitivity syndrome affects sexual development before birth and during puberty. People with this condition have variants in the AR gene in each cell. The body’s cells and tissues are unable to respond to certain male sex hormones (androgens) that are important for normal male sexual development. As a result, affected individuals may have external sex characteristics typical for females or have features of both male and female sexual development.

There are three forms of the condition: complete, partial, and mild.

Forms & Typical Characteristics

Complete Androgen Insensitivity Syndrome (CAIS)

  • Body does not respond to androgens at all.
  • External sex characteristics are typical of females.
  • No uterus; undescended testes located in the pelvis or abdomen.
  • Infertile (no menstruation, cannot conceive).
  • Sparse or absent pubic and axillary hair.

Partial Androgen Insensitivity Syndrome (PAIS)

  • Body’s tissues are partially sensitive to androgens.
  • Genitalia may appear typical for females, typical for males, or have both male and female characteristics.

Mild Androgen Insensitivity Syndrome (MAIS)

  • Born with male‑typical sex characteristics.
  • Often infertile.
  • Tend to experience breast enlargement at puberty.

Frequency

Complete androgen insensitivity syndrome affects 2 to 5 in 100,000 newborn females. Partial androgen insensitivity is thought to be at least as common as the complete form. Mild androgen insensitivity is much less common.

Causes

Variants (mutations) in the AR gene cause androgen insensitivity syndrome. This gene provides instructions for making a protein called an androgen receptor. Androgen receptor proteins interact with androgen hormones, such as testosterone, and help direct male sexual development. The receptor binds to androgens, forming an androgen‑receptor complex that then binds to DNA to regulate genes involved in male sexual development. Androgens and their receptors also influence hair growth and sex drive in both sexes.

Variants in the AR gene prevent androgen receptors from working properly, reducing their ability to bind testosterone and regulate gene activity. If receptors cannot bind androgens, the body cannot use these hormones even when hormone levels are normal.

Learn more about the gene associated with Androgen Insensitivity Syndrome

  • AR

Inheritance

This condition is inherited in an X‑linked recessive pattern. The gene is located on the X chromosome, one of the two sex chromosomes. In males (who have one X chromosome), a single altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a variant would need to occur in both copies to cause the disorder, making it far less common in females. Fathers cannot pass X‑linked traits to their sons.

About 70 percent of all cases are inherited from a parent who carries an altered copy of the AR gene on one of their X chromosomes. The remaining 30 percent result from new (de novo) variants that arise in the egg cell before conception or during early embryonic development.

Other Names for This Condition

  • AIS
  • Androgen receptor deficiency
  • Androgen resistance syndrome
  • AR deficiency
  • DHTR deficiency
  • Dihydrotestosterone receptor deficiency

Additional Information & Resources

Genetic Testing Information

  • Genetic Testing Registry: Androgen resistance syndrome
  • Genetic Testing Registry: Partial androgen insensitivity syndrome

Genetic and Rare Diseases Information Center

  • Androgen insensitivity syndrome
  • Complete androgen insensitivity syndrome
  • Partial androgen insensitivity syndrome

Patient Support and Advocacy Resources

  • National Organization for Rare Disorders (NORD)

Clinical Trials

  • ClinicalTrials.gov

Catalog of Genes and Diseases from OMIM

  • ANDROGEN INSENSITIVITY SYNDROME; AIS

Scientific Articles on PubMed

  • PubMed

References

  • Chen MJ, Vu BM, Axelrad M, Dietrich JE, Gargollo P, Gunn S, Macias CG, McCullough LB, Roth DR, Sutton VR, Karaviti LP. Androgen Insensitivity Syndrome: Management Considerations from Infancy to Adulthood. Pediatr Endocrinol Rev. 2015 Jun;12(4):373-87.
  • Delli Paoli E, Di Chiano S, Paoli D, Lenzi A, Lombardo F, Pallotti F. Androgen insensitivity syndrome: a review. J Endocrinol Invest. 2023 Nov;46(11):2237-2245.
  • Gottlieb B, Pinsky L, Beitel LK, Trifiro M. Androgen insensitivity. Am J Med Genet. 1999 Dec 29;89(4):210-7.
  • Gottlieb B, Trifiro MA. Androgen Insensitivity Syndrome. GeneReviews® [Internet]. 1999 Mar 24 [updated 2017 May 11].
  • Hiort O. Clinical and molecular aspects of androgen insensitivity. Endocr Dev. 2013;24:33-40.
  • Hughes IA, Davies JD, Bunch TI, Pasterski V, Mastroyannopoulou K, MacDougall J. Androgen insensitivity syndrome. Lancet. 2012 Oct 20;380(9851):1419-28.

Frequently Asked Questions

Diagnosis usually begins with a clinical assessment of external genitalia, pubertal development, and family history. Blood tests measure hormone levels (testosterone, luteinizing hormone, estradiol) and may show a male‑typical testosterone level with a female phenotype. A definitive diagnosis requires molecular genetic testing of the AR gene to identify pathogenic variants. Imaging (pelvic ultrasound or MRI) can locate undescended testes and confirm the absence of a uterus.
Most clinicians recommend prophylactic gonadectomy after puberty is complete, typically between ages 16‑18, to allow natural breast development and bone maturation while reducing the long‑term risk of gonadal malignancy (estimated 2‑5 % in CAIS). In partial forms, timing may be individualized based on cancer risk, hormone needs, and patient preference; regular surveillance with ultrasound and tumor markers is an alternative if surgery is delayed.
fter gonadectomy, estrogen replacement is essential to maintain secondary sexual characteristics, bone health, and cardiovascular health. Options include oral estradiol, transdermal patches, or topical gels; the dose is titrated to achieve typical female estradiol levels (≈100‑200 pg/mL). Progestins are not required because there is no uterus. Calcium and vitamin D supplementation, along with weight‑bearing exercise, support bone density.
In complete AIS, infertility is universal because functional testes are absent and no ovaries are present. In partial or mild AIS, some spermatogenesis may persist, but fertility is rare. Options include assisted reproductive technologies using retrieved sperm (if present) with donor eggs, or adoption. Genetic counseling is recommended to discuss the 50 % chance of transmitting the AR variant to offspring and the availability of prenatal or pre‑implantation genetic testing.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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