A patient with genotype 46 XY diagnosed of having androgen insensitivity syndrome. TRUE about androgen insensitivity syndrome is:
## **Core Concept**
Androgen insensitivity syndrome (AIS) is a condition that results from mutations in the androgen receptor gene, leading to resistance to androgen hormones. Individuals with AIS have a 46,XY karyotype but are phenotypically female or have varying degrees of undervirilization due to the inability of their bodies to respond to androgens.
## **Why the Correct Answer is Right**
In AIS, the individual has testes that produce androgens, but due to the androgen receptor defect, these hormones cannot bind properly to their receptors. This results in a failure of masculinization during fetal development, despite the presence of Müller inhibiting substance (MIS) which causes regression of Müllerian ducts, thereby preventing the development of female reproductive structures like the uterus and fallopian tubes. The external genitalia appear female or have a feminized appearance.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, incorrect statements might include claims that AIS individuals have ovaries or that they undergo normal puberty with fertility, which are not accurate.
- **Option B:** Similarly, without the content, we assume any statement contradicting the fundamental aspects of AIS, such as presence of uterus (due to lack of MIS effect or incorrect timing), would be incorrect.
- **Option C:** Any statement suggesting a different karyotype or implying that AIS does not affect sexual differentiation could be considered incorrect.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that individuals with complete androgen insensitivity syndrome (CAIS) typically present with primary amenorrhea and have a female phenotype, despite having testes. They often have a short blind-ending vagina and lack a uterus and fallopian tubes. At puberty, they undergo normal breast development due to aromatization of testosterone to estrogen but do not develop male secondary sexual characteristics.
## **Correct Answer:** . Individuals with Androgen Insensitivity Syndrome have testes.