Swyer Syndrome

At a glance

A condition that affects the development of reproductive and genital organs. Patients present with a functioning Y chromosome but without internal female organs because of an abnormality on the X chromosome that renders the body completely or partially incapable of recognizing the androgens produced.

Synonym

Gonadal Dysgenesis XY-Female Type.

History

Described as pseudohermaphroditism by London obstetrician GIM Swyer in 1955.

Incidence

Disorders of sex development occur in approximately in 1/4,500 births.

Genetic inheritance

Sporadic in most cases but may be X-linked in some cases.

Pathophysiology

Several causative genes have been identified in Swyers Syndrome including ARX, ATRX, CBX2, DHH, DMRT1, GATA4, MAMLD1, MAP3K1, NR0B1, NR5A1, SOX9, SRY, WNT4, WT1, and WWOX. The lack of testis development may be triggered by sex determining region Y, NR5A1, DHH or testis-determining gene loss-of-function mutations, DAX1 or WNT4 duplication or MAP3K1 gain-of-function mutations.

Diagnosis

Clinical features. The finding of “streak gonads” at exploratory laparotomy is pathognomonic. Chromosomal study shows 46 XY karyotype. Sex chromatin study is negative.

Clinical aspects

Patients appear to be normal female phenotype from birth. However, they do not develop secondary sexual characteristics at puberty, do not menstruate, and have “streak gonads.” Most have normal or above-average stature and eunuchoidal proportion. Intelligence is normal. The streak gonads have a high incidence of becoming malignant (gonadoblastoma or germinoma), particularly in association with presence of H-Y gene on the Y chromosome.

Anesthetic considerations

There are no specific anesthetic considerations.

References