XX gonadal dysgenesis

XX xxx gonadal dysgenesis
Classification and external resources
OMIM	233300 XX gonadal dysgenesis 233400 Perrault syndrome
MeSH	D023961
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This syndrome is inherited as an autosomal disease. It affects both males and females but the phenotype differs. In both sexes sensorineural deafness occurs but in females ovarian dysgenesis also occurs.

XX gonadal dysgenesis is a type of female hypogonadism in which no functional ovaries are present to induce puberty in an otherwise normal girl whose karyotype is found to be 46,XX. With nonfunctional streak ovaries she is low in estrogen levels (hypoestrogenic) and has high levels of FSH and LH. Estrogen and progesterone therapy is usually then commenced.

The term “pure gonadal dysgenesis” (PGD) has been used to distinguish a group of patients from gonadal dysgenesis related to Turner syndrome. In the latter a distinct chromosomal aberration is present, while in PGD the chromosomal constellation is either 46,XX or 46,XY. Thus XX gonadal dysgenesis is also referred to as PGD, 46 XX, and XY gonadal dysgenesis as PGD, 46,XY or Swyer syndrome. Patients with PGD have a normal chromosomal constellation but may have localized genetic alterations.

The cause of the condition is often unclear. There are cases where abnormalities in the FSH-receptor have been reported. Apparently either the germ cells do not form or interact with the gonadal ridge or undergo accelerated atresia so that at the end of childhood only a streak gonad is present, unable to induce pubertal changes. As girls' ovaries produce no important body changes before puberty, there is usually no suspicion of a defect of the reproductive system until puberty fails to occur.

Familial cases of XX gonadal dysgenesis are on record.

In one family mutations in the histidyl tRNA synthetase have been described as the cause.

In 1951, Perrault reported the association of gonadal dysgenesis and deafness, now called Perrault syndrome.

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