Complete androgen insensitivity syndrome

Complete androgen insensitivity syndrome (CAIS) is a condition that results in the complete inability of the body's cells to respond to androgens. Androgens are a group of hormones that play a role in male traits and reproductive activity. CAIS is one of the three types of androgen insensitivity syndrome (AIS), which also includes partial androgen insensitivity syndrome (PAIS) and mild androgen insensitivity syndrome (MAIS).

Genetics

CAIS is caused by mutations in the androgen receptor (AR) gene, which is located on the X chromosome. This gene provides instructions for making a protein that allows the body to respond appropriately to androgens. Mutations in the AR gene prevent the androgen receptor from working properly, which means that cells cannot respond to androgens. As a result, individuals with CAIS have a female external appearance despite having a male (46,XY) karyotype.

Symptoms and Diagnosis

Individuals with CAIS typically have:

• Female external genitalia
• Absent or rudimentary Müllerian ducts (which develop into the uterus and fallopian tubes in females)
• Undescended testes (which may be located in the abdomen or inguinal canal)
• Little or no pubic and underarm hair
• Normal breast development

Diagnosis of CAIS is often made during adolescence when menstruation does not begin (primary amenorrhea), or earlier if inguinal hernias are found in infants. Diagnostic tests may include:

• Karyotype analysis to determine the presence of a 46,XY chromosome pattern
• Hormone tests to measure levels of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH)
• Genetic testing to identify mutations in the AR gene

Management

Management of CAIS involves a multidisciplinary approach, including:

• Endocrinologists to monitor hormone levels and manage hormone replacement therapy if needed
• Surgeons to remove undescended testes, which have a risk of becoming cancerous
• Psychologists or psychiatrists to provide support and counseling

Prognosis

Individuals with CAIS typically have a normal lifespan and can lead healthy lives. However, they are infertile due to the absence of functional male or female reproductive organs.

See also

• Androgen insensitivity syndrome
• Partial androgen insensitivity syndrome
• Mild androgen insensitivity syndrome
• Intersex
• Endocrinology