Androgen insensitivity syndrome overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Androgen insensitivity syndrome (AIS) is an undervirilization syndrome in individuals with 46, XY karyotype. The undervirilization can be complete feminization or incomplete virilization with grades of ambiguity. AIS is caused by mutations in the androgen receptor, resulting in resistance to the physiologic activities of androgens. Differing degrees of resistance lead to three phenotypes: a complete form with female-appearing external genitalia, a partial form with a wide range of virilization, and a mild form with only minor undervirilization. AIS presents different challenges depending on whether resistance is complete or partial. Challenges include sex assignment, which impacts other medical decisions such as gonadectomy, hormonal replacement, and other surgical interventions. This review describes medical, psychosocial, and ethical concerns for each stage of development in complete and partial AIS, from the neonatal period to adulthood. These aspects of care should be addressed within an ethical framework by a multidisciplinary team, with the patients and families being the stakeholders in the decision-making process. [1]
Historical Perspective
Case reports compatible with CAIS date back to the 19th century, when hermaphroditism was the technical term for intersex conditions.
Classification
Androgen insensitivity syndrome (AIS) represents a spectrum of defects in androgen action and can be subdivided into three broad phenotypes such as CAIS. PAIS and MAIS.
Pathophysiology
Androgen insensitivity syndrome results from mutations of the gene encoding the androgen receptor. AIS involves variable degree of undervirilization and/or infertility in XY persons of either sex.
Causes
Androgen insensitivity syndrome is caused due to mutations in the X-linked androgen receptor gene. AR gene defects inhibit the normal development of both internal and external genital structures in 46,XY individuals, causing a variety of phenotypes ranging from male infertility to completely normal female external genitalia. [2]
Differentiating Androgen insensitivity syndrome from Other Diseases
Androgen insensitivity syndrome should be differentiated from other more common forms of male undervirilization, including Leydig cell hypoplasia, several uncommon defects of testosterone synthesis, and 5α-reductase deficiency which can produce similar genital anatomy must be excluded. [3]
Epidemiology and Demographics
CAIS has a prevalence of 2 per 100,000 to 5 per 100,000. The incidence of complete AIS is about in 5 in 100,000. (AIS) is typically characterized by evidence of feminization (i.e., undermasculinization). There is no racial predilection for Androgen insensitivity syndrome.
Risk Factors
The risk of gonadal germ cell tumor is low during childhood and adolescence but increases in later adulthood. Benign tumours of non-germ-cell origin include Sertoli cell adenoma and hamartomas.
Screening
Natural History, Complications, and Prognosis
Diagnosis
Diagnostic Criteria
History and Symptoms
Physical Examination
Laboratory Findings
Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Prevention
References
- ↑ Chen MJ, Vu BM, Axelrad M, Dietrich JE, Gargollo P, Gunn S; et al. (2015). "Androgen Insensitivity Syndrome: Management Considerations from Infancy to Adulthood". Pediatr Endocrinol Rev. 12 (4): 373–87. PMID 26182482.
- ↑ Galani A, Kitsiou-Tzeli S, Sofokleous C, Kanavakis E, Kalpini-Mavrou A (2008). "Androgen insensitivity syndrome: clinical features and molecular defects". Hormones (Athens). 7 (3): 217–29. PMID 18694860.
- ↑ Pagon RA, Adam MP, Ardinger HH, Wallace SE, Amemiya A, Bean L, Bird TD, Ledbetter N, Mefford HC, Smith R, Stephens K, Gottlieb B, Trifiro MA. PMID 20301602. Vancouver style error: initials (help); Missing or empty
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