FXPOI involves malfunctioning of the ovaries in a woman younger than age 40 that can mimic some of the symptoms of menopause. Some people may call this early menopause, but FXPOI is much different from menopause.
- In menopause, a woman will likely never have another menstrual period again, but women with FXPOI are much more likely to get periods, even if they come irregularly.
- A woman in menopause has virtually no chance of getting pregnant, but a woman with early stages of FXPOI has at least a low chance of getting pregnant.1 However, in later stages of FXPOI, ovarian function is reduced to the point that the woman could be considered to be in menopause.
Women with FXPOI may experience osteoporosis, a loss of bone tissue causing bones to get thinner and weaker, increasing the risk of bone fractures.
Women with FXPOI also may be more likely to have an autoimmune condition called Addison's disease that affects the body's ability to handle stress.2
Women with FXPOI report higher levels of thyroid problems, depression, and anxiety.3 However, no studies have solidly linked these conditions with FXPOI.
The repeats in the promoter part of the FMR1 gene are unstable, so sometimes the number of repeats increases from one generation to the next. (Visit How do genes cause Fragile X-associated disorders? for more information on the FMR1 gene.)
A premutation gene is less stable than a full mutation gene. Therefore, as it passes from parent to child, a premutation gene might expand to become a full mutation gene. The chances of expansion depend on the number of repeats in the promoter of the premutation gene:
Normal
FMR1 genes that have 5 to 44 CGG repeats in the promoter are considered normal. When these genes are passed from parent to child, the number of repeats does not increase or decrease.4
Intermediate
FMR1 genes with 45 to 54 CGG repeats in the promoter are considered intermediate, or borderline. An intermediate gene may expand from one generation to the next depending on which parent has it.
Mother to Child
Sometimes when a mother passes an intermediate gene to her child, the CGG repeats increase to a number seen with premutations. Research shows that an intermediate gene will not become a full mutation gene in one generation, so, a mother with an intermediate gene will not have a child with a full mutation.
Father to Child
When intermediate genes are transmitted from father to child, they are generally stable and do not increase to premutations.4
Premutations
Premutation (55 to 199 CGG repeats) FMR1 genes can expand to a full mutation from one generation to the next. The risk of expansion depends on which parent has the gene and the number of repeats in that gene.
Mother to Child
An FMR1 gene from the mother with 100 CGG repeats is very likely to expand to a full mutation when passed to the child. An FMR1 gene from the mother with 70 to 79 repeats has about a 30% chance of expanding to a full mutation in one generation.5
Father to Child
Premutations passed from father to child have almost no chance of expanding to full mutations.5
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