HUT (Hutterite)

Inheritance: X-linked
Genes: AR

AS
Testicular feminization syndrome
TFM
Androgen receptor deficiency
AIS
AT deficiency
DHTR deficiency

Genital anomalies

Male feminization

Infertility

Amenorrhea

Androgen Insensitivity Syndrome

Clinical Characteristics

General description (for patients): 

Children with genitalia resembling females are sometimes identified as males when presumed inguinal hernias are found to contain testes.  Examination of chromosomes reveals that these children have an XY (male) configuration instead of the normal female XX.  Such individuals may not come to medical attention until they are older and fail to menstruate or are unable to become pregnant.  There is a large range of genital anomalies, though, and the question of gender may arise during infancy.  At puberty these genetic males may develop all of the secondary sexual characteristics of normal females.

Medical description: 

The older term “testicular feminization” has been replaced by “androgen insensitivity syndrome” since the latter more accurately portrays the biochemical mechanism.  The disorder affects only genetic (XY) males since it is the lack of testicular response to androgens that leads to feminization and anomalies of the genitalia. The phenotypic range of anomalies is wide and in some the genitalia are so characteristically female that the diagnosis is not considered until suspected inguinal hernias are found to contain testicular tissue.  Yet others may escape detection until amenorrhea or infertility become evident.  The vagina, when present, ends blindly, and the uterus and ovaries are absent.  The clitoris is often enlarged and there are various degrees of fusion of labioscrotal folds.  Pubic and axillary hair may be absent after puberty.   Exogenous androgen is ineffective at any stage due to the lack of end organ response.

Genetics: 

Androgen insensitivity syndrome is an X-linked disorder as a result of mutations in the androgen receptor gene (AR) located on the X chromosome (Xq11-q12).  Multiple mutations have been found which may help explain the wide clinical spectrum.  A 2558T>C substitution has been found which abolishes the binding function in the AR gene in a large Hutterite kindred in Manitoba.

Treatment: 

No treatment of the primary genetic defect is possible.  Undiagnosed individuals may live normal lives as females except for infertility and amenorrhea.  Gender assignment and psychological issues may arise if phenotypic females are found to have XY karyotypes as young individuals.

Prognosis: 

Dependent on numerous factors, including gender confusion and late reassignment.  No associated systemic disease is known.

Ancillary treatments and support: 

May require counseling and mental health support.

Specialists and specialty centers: 

Endocrinologist, pediatrician, urologist, psychologist.

References:

Belsham, D.D., Pereira, F., Greenberg, C.R., Lio, S., and Wrogemann, K.:  Leu-676-Pro mutation of the androgen receptor causes complete androgen insensitivity syndrome in a large Hutterite kindred.  Hum. Mutat.  5: 28-33, 1995.  PubMed ID: 7537149

Boehmer, A.L.M., Bruggenwirth, H., Van Assendelft, C., Otten, B.J., Verleun-Mooijman, M.C.T., Niermeijer, M.F., Brunner, H.G., Rouwe, C.W., Waelkens, J.J., Oostdijk, W., Kleijer, W.J., van Der Kwast, T.H., De Vroede, M.A., and Drop, S.L.S.:  Genotype versus phenotype in families with androgen insensitivity syndrome.  J. Clin. Endocr. Metab. 86: 4151-4160, 2001.  PubMed ID: 11549642

Resources:

Androgen Insensitivity Syndrome Support Group

Associated Graphics