Expansion Of Unstable Repeats
Mostrando 1-12 de 26 artigos, teses e dissertações.
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1. Clinical and molecular studies in five brazilian cases of Friedreich ataxia
Friedreich ataxia (FRDA), the most common autosomal recessive ataxia, is caused in 94% of cases by homozygous expansions of an unstable GAA repeat localised in intron 1 of the X25 gene. We have investigated this mutation in five Brazilian patients: four with typical FRDA findings and one patient with atypical manifestations, who was considered to have some o
Publicado em: 2010
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2. Friedreich's Ataxia: Cardiac Evaluation of 25 Patients with Clinical Diagnosis and Literature Review
OBJECTIVE - Cardiac evaluation (clinical, electrocardiographic and echocardiographic) of 25 Brazilian patients with clinical diagnosis of Friedreich's ataxia (FA) related to the frequency and the size of GAA repeats (unstable expansion of trinucleotide repeats that results in the disease). METHODS - Clinical and cardiac study including electrocardiogram and
Arquivos Brasileiros de Cardiologia. Publicado em: 2002-05
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3. The effect of FMR1 CGG repeat interruptions on mutation frequency as measured by sperm typing.
Fragile X syndrome results from the unstable expansion of a CGG repeat within the FMR1 gene. Three classes of FMR1 alleles have been identified, normal alleles with 6-60 repeats, premutations with 60-200 repeats, and full mutations with > 230 repeats. Premutations are exquisitely unstable upon transmission. Normal alleles, while generally stable upon transmi
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4. Both CAG repeats and inverted DNA repeats stimulate spontaneous unequal sister-chromatid exchange in Saccharomyces cerevisiae
Genomic regions containing trinucleotide repeats (TNRs) are highly unstable, as the repeated sequences exhibit a high rate of mutational change, in which they undergo either a contraction or an expansion of repeat numbers. Although expansion of TNRs is associated with several human genetic diseases, the expansion mechanism is poorly understood. Extensive stu
Oxford University Press.
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5. Mutagenic stress modulates the dynamics of CTG repeat instability associated with myotonic dystrophy type 1
The molecular basis of the myotonic dystrophy type 1 is the expansion of a CTG repeat at the DMPK locus. The expanded disease-associated repeats are unstable in both somatic and germ lines, with a high tendency towards expansion. The rate of expansion is directly related to the size of the pathogenic allele, increasing the size heterogeneity with age. It has
Oxford University Press.
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6. Expansion of an FMR1 Grey-Zone Allele to a Full Mutation in Two Generations
Fragile X Syndrome is caused by the expansion of an unstable CGG-repeat tract in the 5′-UTR of the FMR1 gene, which generally results in transcriptional silencing and consequent absence of the FMR1 protein. To date, the smallest premutation allele reported to expand to a full mutation allele in a single generation is 59 CGG repeats. Here, we report a singl
American Society for Investigative Pathology.
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7. CTG repeat instability and size variation timing in DNA repair-deficient mice
Type 1 myotonic dystrophy is caused by the expansion of an unstable CTG repeat in the DMPK gene. We have investigated the molecular mechanisms underlying the CTG repeat instability by crossing transgenic mice carrying >300 unstable CTG repeats in their human chromatin environment with mice knockout for genes involved in various DNA repair pathways: Msh2 (mis
Oxford University Press.
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8. Instability of CAG repeats in Huntington's disease: relation to parental transmission and age of onset.
Huntington's disease (HD) has recently been found to be caused by expansion of a trinucleotide (CAG) repeat within the putative coding region of a gene with an unknown function. We report here an analysis of HD mutation and the characteristics of its transmission in 36 HD families. CAG repeats on HD chromosomes were unstable when transmitted from parent to o
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9. Effects of sequence on repeat expansion during DNA replication
Small DNA repeat tracts are located throughout the human genome. The tracts are unstable, and expansions of certain repeat sequences cause neuromuscular disease. DNA expansions appear to be associated with lagging-strand DNA synthesis and DNA repair. At some sites of repeat expansion, e.g. the myotonic dystrophy type 2 (DM2) tetranucleotide repeat expansion
Oxford University Press.
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10. Increased Instability of Human CTG Repeat Tracts on Yeast Artificial Chromosomes during Gametogenesis
Expansion of trinucleotide repeat tracts has been shown to be associated with numerous human diseases. The mechanism and timing of the expansion events are poorly understood, however. We show that CTG repeats, associated with the human DMPK gene and implanted in two homologous yeast artificial chromosomes (YACs), are very unstable. The instability is 6 to 10
American Society for Microbiology.
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11. Analysis of triplet repeats in the huntingtin gene in Japanese families affected with Huntington's disease.
Huntington's disease (HD) is associated with the expansion of a CAG repeat in the huntingtin gene. Molecular analysis of the repeat in Japanese HD patients and normal controls was performed. The size of the CAG repeat ranged from 37 to 95 repeats in affected subjects and from seven to 29 in normal controls. A significant correlation was found between the age
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12. Trinucleotide repeat length and progression of illness in Huntington's disease.
The genetic defect causing Huntington's disease (HD) has been identified as an unstable expansion of a trinucleotide (CAG) repeat sequence within the coding region of the IT15 gene on chromosome 4. In 50 patients with manifest HD who were evaluated prospectively and uniformly, we examined the relationship between the extent of the DNA expansion and the rate