What is the Difference Between Swyer Syndrome and Androgen Insensitivity?

Swyer syndrome and androgen insensitivity syndrome (AIS) are both disorders of sex development, but they have distinct differences:

Swyer Syndrome:

• Affects females with a 46,XY karyotype.
• Characterized by the failure of sex glands to develop, leading to a lack of puberty and primary amenorrhea.
• Patients have a female external genitalia, normal or tall and eunuchoid stature, bilateral streak gonads, sexual infantilism, and a 46,XY karyotype.
• The main differential diagnosis is mixed gonadal dysgenesis, which shows testicular differentiation on histopathology.
• Treatment may include hormone replacement therapy and, in some cases, surgical intervention for vaginal hypoplasia.

Androgen Insensitivity Syndrome:

• Affects genetically male individuals who show resistance to androgens.
• Causes a person to have some physical traits of a woman, such as a female-like external genitalia.
• There are two main types: complete androgen insensitivity syndrome (CAIS) and partial androgen insensitivity syndrome (PAIS).
• In CAIS, there is no response to androgens, while in PAIS, the androgen receptors can partially respond to androgen stimulation.
• Treatment may include hormone replacement therapy to help develop secondary sexual characteristics and improve fertility.

In summary, the key difference between Swyer syndrome and androgen insensitivity is that Swyer syndrome affects females with a 46,XY karyotype and is characterized by the failure of sex glands to develop, while androgen insensitivity affects genetically male individuals who show resistance to androgens, leading to an inconsistent development of secondary sexual characteristics.

Comparative Table: Swyer Syndrome vs Androgen Insensitivity

Swyer Syndrome and Androgen Insensitivity Syndrome are both disorders of sex development, but they present different clinical features and are caused by different gene mutations. Here is a table summarizing the differences between the two syndromes:

Swyer Syndrome is characterized by a female phenotype with a 46,XY karyotype, normal breast development, and no testes or uterus. It is caused by mutations in genes such as SRY, NROB1, DHH, WNT4, MAP3K1.

Androgen Insensitivity Syndrome (AIS) can range from Partial to Complete. In Complete Androgen Insensitivity Syndrome (CAIS), individuals have a female phenotype with normal breast development, well-formed testes located in the inguinal canal, and a blind vagina pouch with no uterus. It is caused by a mutation in the AR gene.