Gonadal Dysgenesis

Definition - What does Gonadal Dysgenesis mean?

Gonadal dysgenesis is a term used to describe a group of disorders of sexual development in which the formation of the gonads (ovary or testis) is defective either because of abnormalities involving the pattern or number of sex chromosomes or alterations of the genes involved in the formation of the gonads. The poorly developed gonads are substituted with functionless tissue, and are referred to as “streak gonads.” Gonadal dysgenesis may be pure or mixed. Because people with gonadal dysgenesis lack functional ovaries and some may have undescended testes, infertility is inevitable.

FertilitySmarts explains Gonadal Dysgenesis

Gonadal dysgenesis may present in the following ways:

  • Turner syndrome (45XO)
  • Pure gonadal dysgenesis: is used to describe either male or female individuals who have a normal built and height but have streak gonads or undescended testes. They have normal sets of chromosomes (i.e. 46). Types of pure gonadal dysgenesis include a) XX gonadal dysgenesis (46, XX) or b) Swyer syndrome (46, XY).
  • Mixed gonadal dysgenesis: Individuals with a mixed gonadal dysgenesis have an abnormal chromosomal pattern and number (such as 46XY, 45XO). They have an undescended testis on one side and a streak gonad on the opposite side. Likewise, they have a scrotum on the side of the undescended testis and a half uterus and Fallopian tube on the side of the rudimentary ovary. These individuals have a short stature and never have menstrual periods.

Exposure to certain environmental chemicals that can impair the hormonal systems and consequently the development has also been found to trigger gonadal dysgenesis.

The management of these individuals is complicated and requires a multidisciplinary team approach. Individuals with a female habitus, require induction of puberty via hormone replacement therapy (HRT). This allows proper development of breasts, armpit and pubic hair, as well as aids in establishing regular menstrual cycles. Assisted reproduction can help these women to get pregnant. In all the types, the gonads have an increased risk of developing cancer such as gonadoblastoma, and therefore, warrant the consideration of surgical removal.

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