Fragile X syndrome is a genetic disorder that causes a spectrum of complications that includes learning disabilities and cognitive decline. The involvement in men is usually greater than in women. This is because the syndrome is caused by a mutation of a gene located on the X chromosome. Since women have two X chromosomes, if they inherit a chromosome that carries the mutation, they always have another with the normal gene. However, in men, since they only have one X chromosome, if it has the mutation, the man will suffer from fragile X syndrome.
About one in 8,000 women and one in 4,000 men are affected by this disease; while 1 in 600 women are healthy carriers. 20% of healthy women who carry this mutation will develop primary ovarian failure before reaching their 40s. In addition, the ovarian reserve in these women is lower.
When there is a family history of Fragile X syndrome, genetic counselling is necessary. A fragile X study should also be performed in patients with abnormally low ovarian reserve for their age.
Once the syndrome has been diagnosed and in order to avoid having an affected child, treatment should be through in vitro fertilization with preimplantation genetic diagnosis (genetically analyzing the embryos before transferring them) in cases of good ovarian reserve or IVF with ovules of the donor if the woman has a low ovarian reserve and/or early ovarian failure.