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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Endocrinology

The Three Subtypes: CAIS, PAIS, and MAIS

At a Glance

Androgen Insensitivity Syndrome (AIS) exists on a spectrum of three main subtypes: Complete (CAIS), Partial (PAIS), and Mild (MAIS). These categories are defined by the body's ability to respond to androgen hormones, which determines a person's outward physical appearance and internal anatomy.

Androgen Insensitivity Syndrome is not a “one size fits all” condition. Because it exists on a spectrum, doctors categorize AIS into three main subtypes based on how much the body is able to respond to androgen hormones. This response determines a person’s phenotype—their outward physical appearance and internal anatomy.

1. Complete Androgen Insensitivity Syndrome (CAIS)

In CAIS, the body does not respond to androgens at all [1].

  • External Appearance: Individuals have a typical female phenotype at birth and are raised as girls [2][3].
  • Internal Anatomy: They have internal testes (usually located in the abdomen or groin) but do not have a uterus, fallopian tubes, or ovaries [3][4]. Additionally, the vagina may be shortened or end in a “blind pouch” (vaginal hypoplasia), which is an important consideration for future sexual intimacy [5].
  • Puberty: During puberty, the body naturally converts some testosterone into estrogen, leading to typical breast development and female hip rounding [2][1]. However, because there is no uterus, menstruation does not occur (primary amenorrhea), and there is usually very little or no pubic and underarm hair [5][1].
  • Biological Fertility: Because individuals with CAIS do not have ovaries or eggs, and the retained testes do not produce viable sperm, biological parenthood using one’s own genetic material is not possible [1].

2. Partial Androgen Insensitivity Syndrome (PAIS)

PAIS occurs when the body has a partial or limited ability to respond to androgens. This is the most variable subtype, and the physical appearance can range significantly [6].

  • External Appearance: Genitalia may appear ambiguous—meaning they are not clearly male or female—or may include features like hypospadias (where the opening of the urethra is on the underside of the penis) [6][7].
  • Internal Anatomy: Testes are present, and like CAIS, there is typically no uterus [8].
  • Puberty: Pubertal development can be unpredictable. It may involve some masculinization (like voice deepening) but may also include gynecomastia (enlargement of breast tissue) because the body cannot fully use the testosterone it produces [7][9].

3. Mild Androgen Insensitivity Syndrome (MAIS)

MAIS is the mildest form of the condition. The body responds to androgens well enough that the individual typically has a male phenotype [10].

  • External Appearance: Individuals are born with typical male genitalia, though they may have minor variations [11].
  • Puberty and Adulthood: The condition is often not discovered until puberty or later. It may present as mild breast development during puberty or as infertility in adulthood due to low or impaired sperm production [10][12].

The Genotype-Phenotype “Puzzle”

You might assume that a specific mutation in the AR gene (the genotype) would always lead to the exact same physical appearance (the phenotype). However, in AIS, this correlation is surprisingly complex [12].

  • Variable Expression: Two people with the exact same genetic mutation—even members of the same family—can have different physical features. One person might have a CAIS phenotype while another has PAIS [12][6].
  • Why the Difference? Scientists are still studying why this happens. It may be due to other “modifier” genes, variations in how cells process hormones, or somatic mosaicism (where some cells in the body have the mutation and others do not) [13][14].

Clinical Grading Scales

To help navigate this variability, doctors use standardized scales to describe where a person falls on the spectrum:

  • The Quigley Scale: A 7-grade system where Grade 1 represents a typical male appearance (MAIS) and Grade 7 represents a typical female appearance (CAIS) [7].
  • External Masculinization Score (EMS): A scoring system used at birth to help determine the degree of virilization, which can help predict how the body might respond to hormones during puberty [6][15].

Because the genetics alone don’t tell the whole story, your medical team will focus on your or your child’s specific physical development and goals rather than just the lab results [16][6].

Common questions in this guide

What is the difference between CAIS, PAIS, and MAIS?
These are the three subtypes of AIS, based on how the body responds to male hormones. CAIS means no response, resulting in typical female physical traits. PAIS is a partial response with highly variable physical traits, and MAIS is a mild response typically resulting in male physical traits.
Can a person with Complete Androgen Insensitivity Syndrome (CAIS) get pregnant?
No, individuals with CAIS are born without a uterus, fallopian tubes, or ovaries. Because they do not produce eggs and cannot carry a pregnancy, biological parenthood using their own genetic material is not possible.
Why do people with the exact same genetic mutation have different physical features?
The physical appearance in AIS can vary widely even among family members with the exact same genetic mutation. Scientists believe this is due to other modifier genes, variations in how cells process hormones, or having the mutation in only some of the body's cells.
What is the Quigley Scale used for in AIS?
The Quigley Scale is a clinical grading system doctors use to describe where a person falls on the AIS spectrum. It ranges from Grade 1, which represents a typical male appearance, to Grade 7, which represents a typical female appearance.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Where does my or my child's diagnosis fall on the Quigley scale or External Masculinization Score (EMS)?
  2. 2.Since the same mutation can sometimes look different in different people, how will you monitor my child's specific development through puberty?
  3. 3.For a diagnosis of PAIS, what specialists on the multidisciplinary team have the most experience with managing ambiguous genitalia?
  4. 4.Can you explain the options for non-surgical vaginal dilation therapy for individuals with CAIS?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (16)
  1. 1

    Complete androgen insensitivity syndrome in a 15-year-old female with primary amenorrhea and undescended testes: a rare case report.

    Zerin F, Bhadra TK, Sadia R, Shahriar Z

    Radiology case reports 2026; (21(1)):329-332 doi:10.1016/j.radcr.2025.09.075.

    PMID: 41209089
  2. 2

    Familial complete androgen insensitivity syndrome (CAIS): a case series of three siblings with emphasis on diagnosis, management, and psychosocial outcomes.

    Rajaraman V, Vishwanath U, D Cruze L

    Endocrine 2025; (89(2)):627-631 doi:10.1007/s12020-025-04264-1.

    PMID: 40360874
  3. 3

    New mutation causing androgen insensitivity syndrome - a case report and review of literature.

    Maciejewska-Jeske M, Rojewska-Madziala P, Broda K, et al.

    Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology 2019; (35(4)):294-297 doi:10.1080/09513590.2018.1529160.

    PMID: 30449224
  4. 4

    Complete androgen insensitivity syndrome and anti-Müllerian hormone levels before and after laparoscopic gonadectomy.

    Kusumi M, Mitsunami M, Onoue H, et al.

    Gynecology and minimally invasive therapy 2017; (6(3)):126-128 doi:10.1016/j.gmit.2016.11.001.

    PMID: 30254896
  5. 5

    A novel androgen resistance gene mutation (p.G590W) in complete androgen insensitivity syndrome: Emphasizing the need for early gonadectomy and integrated patient care.

    Sun HY, Wang X, Wang LX, Zhang H

    The Journal of international medical research 2025; (53(6)):3000605251350626 doi:10.1177/03000605251350626.

    PMID: 40552659
  6. 6

    Long-term healthcare of people with disorders of sex development: Predictors of pubertal outcomes of partial androgen insensitivity syndrome.

    Fukami M

    EBioMedicine 2018; (37()):29-30 doi:10.1016/j.ebiom.2018.10.026.

    PMID: 30337249
  7. 7

    Partial Androgen Insensitivity Syndrome and Congenital Adrenal Hyperplasia-A Case Report of the Coexistence of Two Rare Diseases in One Patient.

    Krzyścin M, Brodowska A, Furtak G, et al.

    Reports (MDPI) 2025; (8(4)) doi:10.3390/reports8040212.

    PMID: 41283580
  8. 8

    Anti-Müllerian hormone as a marker of steroid and gonadotropin action in the testis of children and adolescents with disorders of the gonadal axis.

    Edelsztein NY, Grinspon RP, Schteingart HF, Rey RA

    International journal of pediatric endocrinology 2016; (2016()):20 doi:10.1186/s13633-016-0038-2.

    PMID: 27799946
  9. 9

    Sexual health in adult women with complete androgen insensitivity syndrome: a single centre cross-sectional study.

    Mangone A, Profka E, Rodari G, et al.

    Journal of endocrinological investigation 2025; (48(8)):1849-1855 doi:10.1007/s40618-025-02592-7.

    PMID: 40304984
  10. 10

    Case Report: Laparoscopic vaginoplasty in a case of partial androgen insensitivity syndrome and a literature review of 16 cases in China.

    Qin H, Liu H, Liu Q, Li B

    Frontiers in surgery 2025; (12()):1702539 doi:10.3389/fsurg.2025.1702539.

    PMID: 41450767
  11. 11

    A Very Early Diagnosis of Complete Androgen Insensitivity Syndrome Due to a Novel Variant in the AR Gene: A Neonatal Case Study.

    Ferrante R, Tumini S, Saltarelli MA, et al.

    Biomedicines 2024; (12(8)) doi:10.3390/biomedicines12081742.

    PMID: 39200206
  12. 12

    Diverse phenotypes and fertility outcomes of patients with androgen insensitivity syndrome in a Chinese family harboring identical AR gene variant.

    Geng H, Tang D, Li K, et al.

    BMC medical genomics 2024; (17(1)):249 doi:10.1186/s12920-024-01990-9.

    PMID: 39394131
  13. 13

    Sex assignment and psychosexual peculiarities of individuals with different forms of androgen insensitivity syndrome: A qualitative study.

    Kristesashvili J, Kobaladze L, Chipashvili M, Jibladze A

    International journal of reproductive biomedicine 2023; (21(12)):985-994 doi:10.18502/ijrm.v21i12.15036.

    PMID: 38370487
  14. 14

    Novel compound variants of the AR and MAP3K1 genes are related to the clinical heterogeneity of androgen insensitivity syndrome.

    Cheng Y, Sun Y, Ji Y, et al.

    Bioscience reports 2020; (40(5)) doi:10.1042/BSR20200616.

    PMID: 32338288
  15. 15

    Predicting puberty in partial androgen insensitivity syndrome: Use of clinical and functional androgen receptor indices.

    Lek N, Tadokoro-Cuccaro R, Whitchurch JB, et al.

    EBioMedicine 2018; (36()):401-409 doi:10.1016/j.ebiom.2018.09.047.

    PMID: 30316867
  16. 16

    Evolution of Gonadal Management in Complete Androgen Insensitivity Syndrome: A 25-Year Retrospective Cohort Study from a Dedicated Differences of Sex Development Service.

    Learner HI, Kalampalikis A, Da Silva P, Clarke SA

    Journal of pediatric and adolescent gynecology 2026; doi:10.1016/j.jpag.2026.02.007.

    PMID: 41698569

This page explains the subtypes of Androgen Insensitivity Syndrome for educational purposes. Always consult your endocrinologist or medical care team for evaluations of specific physical development and diagnostic results.

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