Analysis of CAG repeats in five SCA loci in Mexican population: epidemiological evidence of a SCA7 founder effect

Authors

  • J.J. Magaña,

    Corresponding author
    1. Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
    • Corresponding authors: Jonathan J. Magaña, PhD, Department of Genetics, National Rehabilitation Institute, Calz. México-Xochimilco 289, Col. Arenal Guadalupe, 14389 Mexico City, México.

      Tel.: +52 55 5999 1000x14708;

      fax: +52 55 5603 9127;

      e-mail: maganasm@hotmail.com; jmagana@inr.gob.mx

      and

      Bulmaro Cisneros Vega, PhD,

      Department of Genetics and Molecular Biology,

      CINVESTAV-IPN, Av. Instituto

      Politécnico Nacional No. 2508, Col.

      San Pedro Zacatenco, 07360 Mexico City, México.

      Tel.: +52 55 5061 3339;

      fax: +52 55 5061 3931;

      e-mail: bcisnero@cinvestav.mx

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  • Y.S. Tapia-Guerrero,

    1. Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
    2. Superior Medicine School, National Polytechnic Institute (IPN), Mexico City, Mexico
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  • L. Velázquez-Pérez,

    1. General Direction, Center for Research and Rehabilitation of the Hereditary Ataxias (CIRAH), Holguín, Cuba
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  • C.M. Cerecedo-Zapata,

    1. Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
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  • M. Maldonado-Rodríguez,

    1. Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
    2. Faculty of Chemistry, National Autonomous University of Mexico (UNAM), Mexico City, Mexico
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  • J.S. Jano-Ito,

    1. Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
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  • N. Leyva-García,

    1. Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
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  • R. González-Piña,

    1. Department of Brain Plasticity, INR, Mexico City, Mexico
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  • E. Martínez-Cruz,

    1. Rehabilitation Sub Direction, Rehabilitation and Special Education Center of Veracruz (CREEVER-DIF), Xalapa, Veracruz, Mexico
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  • O. Hernández-Hernández,

    1. Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
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  • B. Cisneros

    Corresponding author
    1. Department of Genetics and Molecular Biology, Center of Research and Advanced Studies (CINVESTAV)-IPN, Mexico City, Mexico
    • Corresponding authors: Jonathan J. Magaña, PhD, Department of Genetics, National Rehabilitation Institute, Calz. México-Xochimilco 289, Col. Arenal Guadalupe, 14389 Mexico City, México.

      Tel.: +52 55 5999 1000x14708;

      fax: +52 55 5603 9127;

      e-mail: maganasm@hotmail.com; jmagana@inr.gob.mx

      and

      Bulmaro Cisneros Vega, PhD,

      Department of Genetics and Molecular Biology,

      CINVESTAV-IPN, Av. Instituto

      Politécnico Nacional No. 2508, Col.

      San Pedro Zacatenco, 07360 Mexico City, México.

      Tel.: +52 55 5061 3339;

      fax: +52 55 5061 3931;

      e-mail: bcisnero@cinvestav.mx

    Search for more papers by this author

  • The authors declare that they have no conflicts of interest.

Abstract

Spinocerebellar ataxias (SCA) are a heterogeneous group of neurodegenerative disorders. CAG (cytosine-adenine-guanine) trinucleotide repeat expansions in the causative genes have been identified as the cause of different SCA. In this study, we simultaneously genotyped SCA1, SCA2, SCA3, SCA6, and SCA7 applying a fluorescent multiplex polymerase chain reaction assay. We analyzed 10 families with SCA (64 patients) from five different communities of Veracruz, a Mexican southeastern state, and identified 55 patients for SCA7 and 9 for SCA2, but none for SCA1, SCA3, or SCA6. To our knowledge, this sample represents one of the largest series of SCA7 cases reported worldwide. Genotyping of 300 healthy individuals from Mexican population and compiled data from different ethnicities showed discordant results concerning the hypothesis that SCA disease alleles arise by expansion of large normal alleles.

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