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Genetic and Rare Diseases Information Center (GARD)

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Swyer syndrome

Other Names for this Disease
  • 46, XY CGD
  • 46, XY complete gonadal dysgenesis
  • 46, XY pure gonadal dysgenesis
  • Gonadal dysgenesis, XY female type
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What is Swyer syndrome?

How might Swyer syndrome be treated?

What is Swyer syndrome?

Swyer syndrome is a condition in which individuals with one X chromosome and one Y chromosome in each cell, the pattern normally found in males, have a female appearance. Those with Swyer syndrome are typically raised as females and have a female gender identity. People with this condition have female external genitalia and a normal uterus and Fallopian tubes. However, they do not have functional gonads (ovaries or testes). Instead, they have undeveloped clumps of tissue, called streak gonads. These abnormal gonads often become cancerous, so they are usually surgically removed early in life. The genes known to cause this condition include the DHH, NR0B1, NR5A1, and SRY genes. Swyer syndrome has different patterns of inheritance depending on the underlying cause.[1]
Last updated: 6/10/2011

How might Swyer syndrome be treated?

The treatment of an individual with Swyer syndrome may depend upon the specific characteristics that an affected individual has. Some individuals require surgery to repair the external genitalia and to create and/or enlarge the vagina. Hormone replacement therapy (HRT) is typically required from puberty onward and usually includes estrogen and progesterone.[2] In addition to helping with normal development of secondary sexual characteristics, HRT can also help prevent bone loss and thinning (osteoporosis) later during life.[3] Abdominal dysgenetic gonads (testes or ovaries with abnormal development) are at increased risk for gonadal tumors and should be surgically removed. Specifically, streak gonads and dysgenetic gonads are at increased risk for gonadoblastoma and should be surgically removed. Although women with Swyer syndrome are infertile, they may become pregnant and carry to term through egg donation.[2]
Last updated: 3/30/2012

  1. Swyer syndrome. Genetics Home Reference. December 2008; Accessed 6/10/2011.
  2. Harry Ostrer. 46,XY Disorder of Sex Development and 46,XY Complete Gonadal Dysgenesis. GeneReviews. September 15, 2009; Accessed 3/30/2012.
  3. Swyer syndrome. NORD. September 4, 2008; Accessed 3/30/2012.