Turners syndrome girls will have no eggs in their ovaries as adults and will be sterile. However we can now preserve the fertility to these girls, if we can get their ovary tissue to freeze well before puberty.
We first reasoned that because of our is studies of X and Y chromosomes in boys and girls, we hypothesized that all pure XO turners girls ( not “mosaics” must have even a few cells with another X chromosome (that is, XX ). If not, they would not be alive. They must have a second X chromosome ( even if only a very small number ), in order to be able to be alive. Otherwise they would have been miscarried. So therefore any surviving turners XO girl must be a mosaic even if routine karyotyping does not reveal this.
So we continued to reason that there must be some XX oocytes (even if only a tiny number) in her ovaries. A tiny number is no problem with modern technology as long as there are indeed some oocytes. Furthermore these young prepubertal oocytes will be extremely fertile, and so you don’t need many of them.
The reason these girls have no eggs when they grow up is not that the ovary is toxic to them or that there is anything wrong with the eggs. It is rather just that there are so few that the normal loss of eggs that all infants go through as they grow up (losing a thousand a month ) going from 1. 5 million at birth to 400,000 as a teenager, will result in no eggs in a turners girl who is born with so few to start with. But the eggs she does have as a little girl are fantastically fertile.
We just completed the first case in a pure XO turners girl and found quite a few good quality follicles with good eggs, proving our contention, and setting the groundwork for many more such children to have their future fertility preserved.
We always contended that mosaic turners with some XX cells would have eggs worth preserving with ovary freezing. But now we know that even so called “pure” turners XO girls also have eggs worth preserving for their future fertility with ovary freezing. So we should be able to restore fertility to most turners syndrome girls.
We analyzed a tiny piece of tissue of the first such turners case to have her ovary frozen pre-pubertally. She was not a mosaic. She was a pure turners xo. Of course we know from our knowledge of the basic science of the x and Y chromosome, that despite the diagnosis from karyotype of pure xo, ALL living turners girls have to be mosaic, or they would not be alive. So we know that these girls, who no one else wants to do because they assume there can be no eggs, and surely they will have no eggs at the time they come of age, these girls should have some few eggs when they are younger. So you need to freeze their ovary tissue before they are gone. And they should be normal and extremely fertile young xx eggs
We are very excited about this, which allows fertility preservation for “pure” non/mosaic xo turners girls.