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Founder effect and ancestral origin of the spinocerebellar ataxia type 7 (SCA7) mutation in Mexican families

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Abstract

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant disease characterized by progressive cerebellar ataxia and macular degeneration causing progressive blindness. It accounts for 1 to 11.6 % of spinocerebellar ataxias (SCAs) cases worldwide and for 7.4 % of SCA7 cases in Mexico. We identified a cluster of SCA7 families who resided in a circumscribed area of Veracruz and investigated whether the high incidence of the disease in this region was due to a founder effect. A total of 181 individuals from 20 families were studied. Four microsatellite markers and one SNP flanking the ATNX7 gene were genotyped and the ancestral origin and local ancestry analysis of the SCA7 mutation were evaluated. Ninety individuals from 19 families had the SCA7 mutation; all were found to share a common haplotype, suggesting that the mutation in these families originated from a common ancestor. Ancestral origin and local ancestry analysis of SCA7 showed that the chromosomal segment containing the mutation was of European origin. We here present evidence strongly suggesting that the high frequency of SCA7 in Veracruz is due to a founder effect and that the mutation is most likely of European origin with greatest resemblance to the Finnish population.

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Acknowledgments

We are grateful to the members of the families for their kind cooperation, especially to Shirley Rojano by her valuable support. Funding for this research was provided by CONACYT 69210. LEGV was supported by MSc fellowship from CONACyT in the Program from Ciencias Bioquímicas at Universidad Nacional Autónoma de México, UNAM.

Conflicts of interest

All authors declare themselves to have no conflict of interest.

Ethical standards

Informed consent was obtained from all subjects, genetic testing was performed as per guidelines of the Institutional Review Board at the National Institute of Neurology and Neurosurgery.

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Author notes

  1. Petra Yescas-Gómez

    Present address: Departamento de Neurogenética, Instituto Nacional de Neurología y Neurocirugía “Manuel Velasco Suárez”, Insurgentes Sur 3877, Col. La Fama, Tlalpan, Mexico City, 14269, Mexico

Authors and Affiliations

  1. Departamento de Neurogenética, Instituto Nacional de Neurología y Neurocirugía “Manuel Velasco Suárez”, Insurgentes Sur 3877, Col. La Fama, Tlalpan, Mexico City, 14269, Mexico

    Lizbeth E. García-Velázquez, Adriana Ochoa-Morales, Leticia Martínez-Ruano & M. Elisa Alonso-Vilatela

  2. Unidad de Genómica de Poblaciones Aplicada a la Salud. Facultad de Química, UNAM - Instituto Nacional de Medicina Genómica, Mexico City, PC, 14610, Mexico

    Lizbeth E. García-Velázquez & Samuel Canizales-Quinteros

  3. Consorcio Genómica Computacional, Instituto Nacional de Medicina Genómica, Mexico City, PC, 14610, Mexico

    Sandra Romero-Hidalgo & Carla Márquez-Luna

  4. Escuela Nacional de Antropología e Historia (ENAH), Molecular Genetics Laboratory, Mexico City, PC, 14030, Mexico

    Víctor Acuña-Alonzo

  5. Consorcio de Enfermedades Cardiovasculares y Óseas, Instituto Nacional de Medicina Genómica, Mexico City, PC, 14610, Mexico

    M. Teresa Villarreal-Molina

Authors
  1. Lizbeth E. García-Velázquez
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  2. Samuel Canizales-Quinteros
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  3. Sandra Romero-Hidalgo
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  4. Adriana Ochoa-Morales
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  5. Leticia Martínez-Ruano
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  6. Carla Márquez-Luna
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  7. Víctor Acuña-Alonzo
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  8. M. Teresa Villarreal-Molina
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  9. M. Elisa Alonso-Vilatela
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  10. Petra Yescas-Gómez
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Corresponding author

Correspondence to Petra Yescas-Gómez.

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García-Velázquez, L.E., Canizales-Quinteros, S., Romero-Hidalgo, S. et al. Founder effect and ancestral origin of the spinocerebellar ataxia type 7 (SCA7) mutation in Mexican families. Neurogenetics 15, 13–17 (2014). https://doi.org/10.1007/s10048-013-0387-4

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  • DOI: https://doi.org/10.1007/s10048-013-0387-4

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