Are there differences in brain morphometry between twins and unrelated singletons? A pediatric MRI study

Authors

  • S. J. Ordaz,

    1. Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
    2. Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA
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  • R. K. Lenroot,

    1. Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
    2. University of New South Wales and Prince of Wales Medical Research Institute, Sydney, Australia
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  • G. L. Wallace,

    1. Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
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  • L. S. Clasen,

    1. Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
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  • J. D. Blumenthal,

    1. Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
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  • J. E. Schmitt,

    1. Virginia Institute for Psychiatric and Behavioral Genetics and Departments of Psychiatry and Human Genetics, Virginia Commonwealth University, Richmond, VA, USA
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  • J. N. Giedd

    Corresponding author
    1. Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD
      J. N. Giedd, MD, Building 10, Room 4C110, 10 Center Drive, Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD 20892, USA. E-mail:jg@nih.gov
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J. N. Giedd, MD, Building 10, Room 4C110, 10 Center Drive, Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD 20892, USA. E-mail:jg@nih.gov

Abstract

Twins provide a unique capacity to explore relative genetic and environmental contributions to brain development, but results are applicable to non-twin populations only to the extent that twin and singleton brains are alike. A reason to suspect differences is that as a group twins are more likely than singletons to experience adverse prenatal and perinatal events that may affect brain development. We sought to assess whether this increased risk leads to differences in child or adolescent brain anatomy in twins who do not experience behavioral or neurological sequelae during the perinatal period. Brain MRI scans of 185 healthy pediatric twins (mean age = 11.0, SD = 3.6) were compared to scans of 167 age- and sex-matched unrelated singletons on brain structures measured, which included gray and white matter lobar volumes, ventricular volume, and area of the corpus callosum. There were no significant differences between groups for any structure, despite sufficient power for low type II (i.e. false negative) error. The implications of these results are twofold: (1) within this age range and for these measures, it is appropriate to include healthy twins in studies of typical brain development, and (2) findings regarding heritability of brain structures obtained from twin studies can be generalized to non-twin populations.

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