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Asian origin for the worldwide-spread mutational event in Machado-Joseph disease

Martins, S; Calafell, F; Gaspar, C; Wong, VCN; Silveira, I; Nicholson, GA; Brunt, ER; ... Sequeiros, J; + view all (2007) Asian origin for the worldwide-spread mutational event in Machado-Joseph disease. ARCH NEUROL-CHICAGO , 64 (10) 1502 - 1509.

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Abstract

Background: Machado-Joseph disease is the most frequent dominant ataxia worldwide. Despite its frequency and presence in many populations, only 2 founder mutations have been suggested to explain its current geographic distribution.Objectives: To trace back in history the main mutational events in Machado-Joseph disease, we aimed to assess ancestral haplotypes and population backgrounds, to date the mutations, and to trace the routes and time of introduction of the founder haplotypes in different populations.Design, Setting, and Participants: We studied 264 families with Machado-Joseph disease from 20 different populations. Six intragenic single-nucleotide polymorphisms were used to determine ancestral mutational events; 4 flanking short tandem repeats were used to construct extended haplotypes and measure accumulation of genetic diversity over time within each lineage.Results: The worldwide-spread lineage, TTACAC, had its highest diversity in the Japanese population, where we identified the ancestral short tandem repeat-based haplotype. Accumulated variability suggested a postneolithic mutation, about5774 +/- 1116 years old, with more recent introductions in North America, Germany, France, Portugal, and Brazil. As to the second mutational event, in the GTGGCA lineage, only 7 families ( of 71 families) did not have Portuguese ancestry, although gene diversity was again smaller in Portuguese families (0.44) than in non-Portuguese families (0.93).Conclusions: The worldwide-spread mutation may have first occurred in Asia and later been diffused throughout Europe, with a founder effect accounting for its high prevalence in Portugal; the other Machado-Joseph disease lineage is more recent, about 1416 +/- 434 years old, and its dispersion may be explained mainly by recent Portuguese emigration.

Type: Article
Title: Asian origin for the worldwide-spread mutational event in Machado-Joseph disease
Keywords: DOMINANT CEREBELLAR-ATAXIA, SPINOCEREBELLAR ATAXIA, GENETIC DISORDER, REPEAT EXPANSION, CAG-REPEAT, FAMILIES, HAPLOTYPE, DEGENERATION, FREQUENCY, POPULATIONS
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Clinical and Movement Neurosciences
URI: http://discovery.ucl.ac.uk/id/eprint/80451
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