Male premutation carriers presenting between 55 and 200 CGG repeats in the Fragile-X-associated (FMR1) gene are at risk of developing Fragile X Tremor/Ataxia Syndrome (FXTAS), and females undergo Premature Ovarian Failure (POF1).
This small case-control study failed to find associations between CGG repeat sizes or AGG interruptions in FMR1 and premature ovarian failure in Chinese women.
The genetic analysis performed on a cohort of patients with POI revealed that 8% had FMR1 premutation and only one patient a previously known variant of BMP-15 gene.
A recent study has reported that the POI in BRCA1/2-mutation carriers is most likely due to low FMR1 sub-genotype (CGG n < 26) and the authors also suggested that low sub-genotypes of the FMR1 gene might be important to rescue the BRCA1/2 embryos, which would otherwise be embryonically-lethal.
To identify the role of both genetic (number of CGG repeats in the FMR1 gene) and autoimmune factors (anti-ovarian antibodies) in premature ovarian failure (POF).
These results together suggest that FMR1 premutation RNA could cause the POI associated with FMR1 premutation carriers, and the Akt/mTOR pathway may serve as a therapeutic target for FXPOI.
Carriers of a premutation (CGG repeat length 55-200) in the fragile X mental retardation (FMR1) gene are at risk for primary ovarian insufficiency (FXPOI).
DNA and RNA samples were isolated from 74 patients with idiopathic POF to evaluate quantitatively the expression of FMR1 in leukocytes and CGG triplet number on FMR1 gene alleles. mRNA levels were normalized and compared with those of control women.
The prevalence of having >36 CGG repeats in the FMR1 gene was significantly higher in patients with POI than in controls, and age at the onset of amenorrhea was significantly lower in patients with >38 repeats.
The frequency of X-chromosome mosaicism in women with sporadic POF has been found to range between 3 and 10%, whereas the prevalence of POF in carriers of the FMR1 premutation is estimated to range between 13 and 25%.
The most common known genetic cause of 46,XX POI is the expansion of a CGG repeat to 55 to 199 copies in the 5' untranslated region in the X-linked FMR1 gene.
To increase awareness of the unique clinical and ethical considerations invoked by the request of a patient with premature ovarian failure (POF) and her nulliparous sister, both with intermediate-size mutations in fragile X mental retardation 1 (FMR1), to pursue sibling ovum donation.
The FMR1 gene is involved in three different syndromes: fragile X syndrome (FXS), primary ovarian insufficiency (POI), and fragile X-associated tremor/ataxia syndrome (FXTAS) in older patients.