Complete Androgen Insensitivity Syndrome (CAIS)

View a glossary of key terms and definitions commonly used in discussions about sex development. 

What is CAIS? 

Complete Androgen Insensitivity Syndrome (CAIS) is a genetic condition characterized by the body's inability to respond to testosterone, despite having 46,XY chromosomes and functional testes that produce this hormone. Individuals with CAIS are typically born with external genitalia that appear typical for female development, including a clitoris and labia. However, internally, they possess testicles and lack a uterus.

What Causes CAIS? 

CAIS primarily results from a mutation or alteration in the androgen receptor gene (AR), rendering it nonfunctional. Without a functioning androgen receptor, the body does not respond to testosterone, leading to the development of female external genitalia despite possessing male chromosomes. CAIS can be inherited within families or occur spontaneously in an individual.

How is CAIS Diagnosed?

Diagnosis of CAIS can occur at various stages of life and for different reasons:

• Genetic testing during pregnancy or after birth may reveal 46,XY chromosomes despite typical female external genitalia.
• In adolescence, the absence of menstruation coupled with imaging studies (such as ultrasound) revealing the absence of a uterus and the presence of testicles in the groin, pelvis, or abdomen can lead to diagnosis.
• Elevated levels of testosterone in hormone tests or the identification of testicles during hernia surgery may also prompt diagnosis.

How is CAIS Treated?

Treatment strategies for CAIS aim to address both medical and psychological needs:

• Psychological support: Counseling and support services are crucial for individuals and families to navigate the complexities of CAIS.
• Gonadal management: Due to an increased risk of tumor development, discussion of gonadal management, including the potential removal of testicles, is important.
  Hormone supplementation: Hormone therapy, such as estrogen or testosterone supplementation, may be recommended, particularly if gonads are removed.
• Vaginal dilation: For individuals desiring vaginal function, vaginal dilation techniques may be employed to maintain vaginal depth and elasticity.
• Surgical interventions: Some individuals opt for surgical creation of a vagina, often performed by specialized teams like those found in the Collaborative Advanced Reconstructive Evaluation (CARE) Clinic.

Individualized care plans, developed in collaboration with healthcare providers specializing in endocrinology, genetics, gynecology, and psychology, are essential for optimizing the health and well-being of individuals with CAIS.

While living with CAIS presents unique challenges, with comprehensive medical care, support, and understanding, individuals can lead fulfilling lives. It's vital for healthcare providers to offer compassionate and inclusive care, respecting each individual's autonomy and identity.