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Disease Profile

Swyer syndrome

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

Adolescent

ICD-10

Q99.1

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

46, XY CGD; 46, XY complete gonadal dysgenesis; 46, XY pure gonadal dysgenesis;

Categories

Blood Diseases; Congenital and Genetic Diseases; Endocrine Diseases;

Summary

Swyer syndrome is a genetic condition affecting sexual organ development, classified as a disorder of sex development (DSD). In Swyer syndrome, people with one X chromosome and one Y chromosome, normally present in males, are born with female external genitalia and underdeveloped gonads (ovaries or testes) known as streak gonads. Most people with Swyer syndrome are raised as females. Adolescents with this condition do not go through normal puberty and are infertile. Some cases of Swyer syndrome are caused by genetic alterations (mutations) in one of several genes, but in some cases the cause is unknown. The inheritance pattern depends on the responsible gene. This condition is diagnosed based on the chromosome results, clinical examination, and imaging studies. Treatment includes removal of streak gonads to prevent cancer and hormone replacement therapy from puberty onward. While women with Swyer syndrome are infertile, they may become pregnant with the use of donated eggs.[1][2][3]

Symptoms

The following list includes the most common signs and symptoms in people with Swyer syndrome. These features may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list also does not include every symptom or feature that has been described in Swyer syndrome.[4][2]

Signs and symptoms may include:

  • Female external genitals
  • 46,XY chromosomes
  • Delayed or absent puberty
  • Absent menstrual periods (primary amenorrhea)
  • Undeveloped ovaries or testes (streak gonads)

Most people with Swyer syndrome are raised and identify as female. They may have no symptoms until adolescence when they do not go through puberty and or start their periods. Hormone replacement therapy can help to develop secondary sexual characteristics such as breasts, pubic hair, and a regular menstrual cycle. People with Swyer syndrome are infertile, but may be able to get pregnant through egg donation and artificial reproductive technologies.[4][2][3]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Hypogonadotropic hypogonadism
0000044
Male pseudohermaphroditism
0000037
Polycystic ovaries
0000147
Testicular dysgenesis
0008715
Percent of people who have these symptoms is not available through HPO
Abnormality of female external genitalia
Abnormal female external genitalia
0000055
Absence of secondary sex characteristics
0008187
Ambiguous genitalia
Ambiguous external genitalia
Ambiguous external genitalia at birth
Intersex genitalia

[ more ]

0000062
Elevated circulating follicle stimulating hormone level
0008232
Elevated circulating luteinizing hormone level
0011969
Gonadal dysgenesis
0000133
Gonadoblastoma
0000150
Primary amenorrhea
0000786
Sex reversal
0012245
Tall stature
Increased body height
0000098
Y-linked inheritance
0001450

Cause

About 10-20% of cases are caused by genetic alterations (mutations) in the SRY gene.[2][3] At least ten different other genes have been associated with Swyer syndrome. In many cases, the cause of Swyer syndrome remains unknown.[3][5]

Diagnosis

Swyer syndrome is diagnosed based on the medical history, clinical examination, presence of characteristic features, chromosome results, and imaging studies such as a MRI or CT scan. Often people with this condition are not diagnosed until adolescence or adulthood due to delayed puberty, not having menstrual cycles, or infertility. In some cases, Swyer syndrome is diagnosed at birth based on a prenatal test and ultrasound findings.[1][2][3]

Treatment

The treatment of a person with Swyer syndrome may depend on the specific characteristics that each person has. Some people need surgery to repair the external genitalia and to create and/or enlarge the vagina. Hormone replacement therapy (HRT) is typically needed from puberty onward and usually includes estrogen and progesterone.[6] In addition to helping with normal development of secondary sexual characteristics, HRT can help prevent bone loss and thinning (osteoporosis) later in life. Abdominal dysgenetic gonads (testes or ovaries with abnormal development) or streak gonads, which are common in people with Swyer syndrome, are at increased risk for gonadal tumors such as gonadoblastoma and should be surgically removed. Although women with Swyer syndrome are infertile, they may become pregnant and carry to term through egg donation.[6]

Treatment for Swyer syndrome includes surgery to remove undeveloped gonads (streak gonads) and hormone replacement therapy during adolescence. Streak gonads are removed as soon as possible because of the risk of them becoming cancerous. Women with Swyer syndrome are infertile, but pregnancy is possible through egg donation and artificial reproductive technologies.[1][2][3]

Specialists who might be involved in the care of someone with Swyer syndrome include:

  • Endocrinologist (specialist in hormones)
  • Gynecologist
  • Psychologist 

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • Genetics Home Reference (GHR) contains information on Swyer syndrome. This website is maintained by the National Library of Medicine.
    • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

      In-Depth Information

      • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
      • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Swyer syndrome. Click on the link to view a sample search on this topic.

        References

        1. Mayur P, Parikshaa G, Anil B, Shalini G, Arvind R. 'Size does matter': Prophylactic gonadectomy in a case of Swyer syndrome. J Gynecol Obstet Hum Reprod. 2019; 48(4):283-286. https://pubmed.ncbi.nlm.nih.gov/30690088.
        2. Meyer KF, Freitas Filho LG, Silva KI, Trauzcinsky PA, Reuter C, Souza MBM. The XY female and SWYER syndrome. Urol Case Rep. 2019;26:100939. Published 2019 Jun 7.. 2019; 26:100939. https://pubmed.ncbi.nlm.nih.gov/31275808.
        3. Banoth M, Naru RR, Inamdar MB, Chowhan AK. Familial Swyer syndrome: a rare genetic entity. Gynecol Endocrinol. 2018; 34(5):389-393. https://pubmed.ncbi.nlm.nih.gov/29069951.
        4. Swyer syndrome. National Organization for Rare Disorders (NORD). Updated 2019; https://rarediseases.org/rare-diseases/swyer-syndrome/.
        5. 46,XY Sex reversal 1; SRXY1; phenotypic series. Online Mendelian Inheritance in Man (OMIM). Updated Aug 20, 2019; https://omim.org/entry/400044.
        6. Harry Ostrer. 46,XY Disorder of Sex Development and 46,XY Complete Gonadal Dysgenesis. GeneReviews. September 15, 2009; https://www.ncbi.nlm.nih.gov/books/NBK1547/. Accessed 3/30/2012.

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