CGG repeat sizing in the FMR1 gene in Indian women with premature ovarian failure

Chatterjee, Suparna; Maitra, Anurupa; Kadam, Sandeep; Patel, Zarine; Gokral, Jyotsna; Meherji, Pervin

doi:10.1016/s1472-6483(10)60086-7

Cited by 26 publications

(20 citation statements)

References 38 publications

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“…In addition, women carrying either alleles with ,28 repeats or alleles with .33 repeats presented with reduced AMH levels, suggesting diminished ovarian reserve in these CGG repeat ranges (Gleicher et al, 2009a). The results of these and a few other studies (Chatterjee et al, 2009;Gleicher et al, 2010a,b;Karimov et al, 2011) suggest that the number of CGG repeats in the normal and intermediate range might also affect the ovarian ageing process over time and thereby the timing of menopause. Therefore, we aimed to investigate the association between the number of CGG repeats in the normal and intermediate range (up to 55 repeats) and age at natural menopause using a large cohort of Dutch post-menopausal women.…”

Section: Introductionmentioning

confidence: 78%

The association of CGG repeats in the FMR1 gene and timing of natural menopause

et al. 2012

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Earlier observations suggesting that the number of CGG repeats in the normal and intermediate range is associated with the individual variation of the ovarian ageing process could not be confirmed in the current, large sample size study. A relation between the number of CGG repeats in the normal and intermediate range and age at natural menopause appeared to be absent. This finding questions the role of CGG repeat sizes in the ovarian ageing process.

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Section: Introductionmentioning

confidence: 78%

The association of CGG repeats in the FMR1 gene and timing of natural menopause

et al. 2012

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“…275 In another study, the rise in serum concentration of FSH was associated with CGG repeat size within the normal range but exceeding 30 CGGs, both in 80 females with POI and 70 controls. 276 …”

Section: Do the Intermediate Size (Gz) Alleles Cause Abnormal Phenotymentioning

confidence: 99%

Unstable Mutations in the FMR1 Gene and the Phenotypes

Loesch

Hagerman

2012

Advances in Experimental Medicine and Biology

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Fragile X syndrome (FXS), a severe neurodevelopmental anomaly, and one of the earliest disorders linked to an unstable ('dynamic') mutation, is caused by the large (>200) CGG repeat expansions in the noncoding portion of the FMR1 (Fragile X Mental Retardation-1) gene. These expansions, termed full mutations, normally silence this gene's promoter through methylation, leading to a gross deficit of the Fragile X Mental Retardation Protein (FMRP) that is essential for normal brain development. Rare individuals with the expansion but with an unmethylated promoter (and thus, FMRP production), present a much less severe form of FXS.However, a unique feature of the relationship between the different sizes of CGG expanded tract and phenotypic changes is that smaller expansions (<200) generate a series of different clinical manifestations and/or neuropsychological changes. The major part of this chapter is devoted to those FMR1 alleles with small (55-200) CGG expansions, termed 'premutations', which have the potential for generating the full mutation alleles on mother-offspring transmission, on the one hand, and are associated with some phenotypic changes, on the other. Thus, the role of several factors known to determine the rate of CGG expansion in the premutation alleles is discussed first. Then, an account of various neurodevelopmental, congnitive, behavioural and physical changes reported in carriers of these small expansions is given, and possible association of these conditions with a toxicity of the elevated FMR1 gene's transcript (mRNA) is discussed.The next two sections are devoted to major and well defined clinical conditions associated with the premutation alleles. The first one is the late onset neurodegenerative disorder termed fragile Xassociated tremor ataxia syndrome (FXTAS). The wide range of clinical and neuropsychological manifestations of this syndrome, and their relevance to elevated levels of the FMR1 mRNA, are described. Another distinct disorder linked to the CGG repeat expansions within the premutation range is fragile X-associated primary ovarian insufficiency (FXPOI) in females, and an account of the spectrum of manifestations of this disorder, together with the latest findings suggesting an early onset of the ovarian changes, is given.In the following section, the most recent findings concerning the possible contribution of FMR1 'grey zone' alleles (those with the smallest repeat expansions overlapping with the normal range

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“…The frequency of premutation carriers among women with the sporadic form of POI ranges between 1.6% and 3.3% (27,(28)(29)(30)(31) in Caucasian populations, and one study has described a frequency of 4.8% in a group of screened Slovenian patients (32). A study of 80 Indian patients with POI revealed that none of them had CGG repeats within the premutation range (33). The data from these studies and the present study indicate that fewer Asian than Caucasian patients with POI have CGG repeats in the premutation range (11,29,31,32).…”

Section: Figurementioning

confidence: 99%