Women with a known premutation
Studies show that:
However, many women with premutations are able to conceive and family planning is recommended rather than assuming decreased fertility. The decrease in fertility is related to increased levels of some hormones, particularly FSH, and a decreased length of a phase of the menstrual cycle called the follicular phase.
- approximately 20-28% of women with an FMR1 premutation experience Fragile X-associated primary ovarian insufficiency (FXPOI) – menopause occurring prior to the age of 40
- another 23% experience early menopause – menopause occurring prior to the age of 45.
- all women with premutations have some decrease in ovarian function (decreased fertility).
- some women who are carriers are at risk for anxiety and depression.
It is recommended that all women with premutations have FSH levels evaluated and monitored throughout their childbearing years.
Women with a known full mutation
They do not appear to be at risk for these conditions.
Women with Primary Ovarian Insufficiency (POI) and no known family history of Fragile X
Studies show that women who have POI of unknown cause have a 1/50 chance of being a premutation carrier of the FMR1 gene, the gene that causes Fragile X syndrome.
Women with POI and a family history of female relatives with POI
These women have a 1/15 chance of carrying this premutation. Given that carriers of the FMR1 premutation have a significant risk of having a child with Fragile X syndrome, testing for the FMR1 premutation in women with POI is highly recommended.
Premutation leads to decrease in fertility
While all women with a premutation experience some decrease in fertility, many are still able to conceive.