How can there be menstruation in Turner syndrome where there's streak gonads?

how can there be menstruation in Turner syndrome where there’s streak gonads?

Turner syndrome (TS) is typically characterized by streak gonads, which are underdeveloped and non-functional ovaries that result in primary ovarian insufficiency and consequently, amenorrhea (absence of menstruation). However, menstruation can occur in some cases of Turner syndrome due to the following reasons:

Mosaicism

  • Definition: Mosaicism in Turner syndrome means that not all cells in the body have the typical 45,X karyotype. Some cells might have a different karyotype, such as 46,XX or 47,XXX, which can include functional ovarian tissue.
  • Impact: If a significant proportion of ovarian cells have a normal karyotype, they might produce enough estrogen and progesterone to induce menstruation and even spontaneous puberty.

Hormone Replacement Therapy (HRT)

  • Purpose: Hormone replacement therapy is often used in Turner syndrome to induce the development of secondary sexual characteristics and to stimulate menstruation.
  • Mechanism: HRT typically involves the administration of estrogen and progesterone, which can mimic the natural menstrual cycle and result in withdrawal bleeding similar to menstruation.

Presence of Functional Ovarian Tissue

  • Rare Cases: In some rare instances, individuals with Turner syndrome may have residual functional ovarian tissue capable of producing hormones.
  • Outcome: This residual ovarian function might be enough to initiate spontaneous menstruation, although it is usually transient and diminishes over time as ovarian function further declines.

Induction of Puberty

  • Medical Induction: Physicians may induce puberty using hormone therapies to ensure the development of secondary sexual characteristics, uterine development, and bone health.
  • Regular Cycles: Cyclic hormone replacement therapy can lead to regular menstrual cycles in girls with Turner syndrome who otherwise would not menstruate due to gonadal dysgenesis.

Summary

Menstruation in Turner syndrome, despite the presence of streak gonads, can occur due to mosaicism leading to some functional ovarian tissue, hormone replacement therapy, or, rarely, the presence of residual functional ovarian tissue. Each of these factors can contribute to the production of hormones necessary to induce menstruation.