The fragile X syndrome.

Vries, Bert B.A. de; Halley, Dicky; Oostra, Ben A.; Niermeijer, Martinus F.

doi:10.1136/jmg.35.7.579

Cited by 143 publications

(74 citation statements)

References 158 publications

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“…The size and AGG-interruption patterns of the FMR1 (CGG) n trinucleotide repeat have been identified as major factors contributing to the risk of developing fragile X syndrome (de Vries et al 1998 ;Ashley-Koch et al 1998). As the population prevalence of both the FMR1 greyzone (41-54 CGG repeats), premutation (55-200 CGG repeats) and full mutation alleles ( 200 CGG repeats) have important implications for the rational planning and provision of genetic services, there have been several national and international surveys of allelic diversity at FMR1 and associated polymorphic loci (Rousseau et al …”

Section: mentioning

confidence: 99%

Genetic diversity at the FMR1 locus in the Indonesian population

Faradz

Pattiiha²,

Leigh

et al. 2000

Annals of Human Genetics

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We report an analysis of allelic diversity at short tandem repeat polymorphisms within the fragile XA locus in 1069 male volunteers from twelve Indonesian sub-populations. An odd numbered allele of DXS548 was found at high frequency in all Indonesian populations. Greater allelic diversity was identified at the loci under study than has been previously reported for an Asian population. These differences distinguish the Indonesian population from all previously reported Asian, European and African populations. A high frequency of small premutation alleles, 4\120 (3n3%, 95% CI 0n9-8n3 %), was identified in the Moluccan population of Hiri Island. The size and AGG-interruption patterns of the FMR1 (CGG) n trinucleotide repeat have been identified as major factors contributing to the risk of developing fragile X syndrome (de Vries et al. 1998 ;Ashley-Koch et al. 1998). As the population prevalence of both the FMR1 greyzone (41-54 CGG repeats), premutation (55-200 CGG repeats) and full mutation alleles ( 200 CGG repeats) have important implications for the rational planning and provision of genetic services, there have been several national and international surveys of allelic diversity at FMR1 and associated polymorphic loci (Rousseau et al.

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Section: mentioning

confidence: 99%

Genetic diversity at the FMR1 locus in the Indonesian population

Faradz

Pattiiha²,

Leigh

et al. 2000

Annals of Human Genetics

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“…Intermediate or grey zone alleles are poorly defined. Boundaries for the grey zone range vary among studies, from 34 or 35 CGG repeats for the lower boundary to 58/60 repeats for the upper boundary [7][8][9][10]. These alleles are often transmitted stably, but are more likely to exhibit unstable transmission with increasing size within this range.…”

Section: Introductionmentioning

confidence: 99%

“…Premutation alleles have a moderate expansion of the repeat (from 50 to ~200 units), they are unmethylated on an active X chromosome and do not affect FMR1 expression. CGG repeat expansion over 200 is the basis for CpG island methylation, leading to silencing of the FMR1 gene [7]. Intermediate or grey zone alleles are poorly defined.…”

Section: Introductionmentioning

confidence: 99%

FMR1 Linked haplotype analysis in a mentally retarded male population

Daneberga¹,

Pronina²,

Lāce

et al. 2011

Open Medicine

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AbstractFragile X syndrome is caused by dynamic mutation of FMR1 gene CpG island CGG repeats. The underlying mutational mechanism is not fully understood. Different microsatellite markers and SNP have previously been reported as markers associated with FMR1 CGG repeat instability. The aim of the present study was to identify specific haplotypes among Latvian FXS patients and the control group with respect to allelic stability. Eleven male FXS patients and 122 control male patients participated in the study. In total, 27 different DXS548-FRAXAC1-ATL1-FRAXAC2 haplotypes were found. The prevalent haplotype in the control group was 7-4-A-5+ (rel. frequency 0.327). The prevalent haplotype associated with the FXS group was 2-2-G-4 (rel. frequency 0.818; p < 0.0001). Grey zone alleles with a long uninterrupted CGG tract at the 3’ end were significantly associated with the 2-2-G-4 haplotype (p = 0.0022). Our findings suggest that, for the Latvian population, the haplotype 2-2-G-4 is a marker of CGG tract instability. We conclude that a founder effect could not be an explanation for our findings on the basis of heterogeneity exhibited by the Latvian population and lack of studies throughout this geographical region. This data may provide evidence of different mutational pathways of expansion in the Baltic States region.

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“…Affected individuals exhibit moderate-to-severe mental retardation and developmental delays as well as characteristic physical features including macroorchidism and facial abnormalities (Schapiro et al, 1995). FXS is also commonly accompanied by neuropsychiatric problems such as hyperactivity, autism, attention disorders, and seizures (de Vries et al, 1998). The syndrome is most often caused by a trinucleotide (CGG) repeat expansion in the fragile X mental retardation 1 (FMR1) gene, leading to DNA methylation and transcriptional silencing; other mutations involving the FMR1 gene can cause FXS if they prevent production or alter functional domains of the encoded protein, the fragile X mental retardation protein (FMRP) (O'Donnell and Warren, 2002).…”

Section: Introductionmentioning

confidence: 99%

Age-Dependent and Selective Impairment of Long-Term Potentiation in the Anterior Piriform Cortex of Mice Lacking the Fragile X Mental Retardation Protein

Larson¹,

Jessen²,

Kim³

et al. 2005

J. Neurosci.

121

112

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Synaptic function and plasticity were studied in mice lacking the fragile X mental retardation protein (FMRP), a model for the fragile X mental retardation syndrome. Associational connections were studied in slices of anterior piriform (olfactory) cortex, and Schaffercommissural synapses were studied in slices of hippocampus. Knock-out (KO) mice lacking FMRP were compared with congenic C57BL/6J wild-type (WT) controls. Input-output curves and paired-pulse plasticity were not significantly altered in KO compared with WT mice in either the olfactory cortex or hippocampus. Long-term potentiation (LTP) induced by theta burst stimulation in the anterior piriform cortex was normal in KO mice aged Ͻ6 months but was impaired in KO mice aged Ͼ6 months. The deficit in LTP was significant in mice aged 6 -12 months and more pronounced in mice aged 12-18 months. Similar differences between WT and KO mice were seen whether LTP was induced in the presence or absence of a GABA A receptor blocker. Postsynaptic responses to patterned burst stimulation in KO mice showing impaired LTP were not significantly different from those in WT mice, suggesting that the LTP deficit was not caused by alterations in circuit properties. No differences in hippocampal LTP were observed in WT and KO mice at any ages. The results indicate that FMRP deficiency is associated with an age-dependent and region-selective impairment in long-term synaptic plasticity.

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The fragile X syndrome.

Abstract: The fragile X syndrome is characterised by mental retardation, behavioural features, and physical features, such as a long face with large protruding ears and macro-orchidism. In 1991, after identification of the fragile X mental retardation (FMRI) (JMed Genet 1998;35:579-589)

Cited by 143 publications

References 158 publications

Genetic diversity at the FMR1 locus in the Indonesian population

Genetic diversity at the FMR1 locus in the Indonesian population

FMR1 Linked haplotype analysis in a mentally retarded male population

Age-Dependent and Selective Impairment of Long-Term Potentiation in the Anterior Piriform Cortex of Mice Lacking the Fragile X Mental Retardation Protein

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