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Neuroimage. 2013 Dec;83:962-8. doi: 10.1016/j.neuroimage.2013.07.052. Epub 2013 Jul 25.

High resolution whole brain imaging of anatomical variation in XO, XX, and XY mice.

Author information

1
Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD, USA. Electronic address: raznahana@mail.nih.gov.

Abstract

The capacity of sex to modify behavior in health and illness may stem from biological differences between males and females. One such difference--fundamental to the biological definition of sex--is inequality of X chromosome dosage. Studies of Turner Syndrome (TS) suggest that X-monosomy profoundly alters mammalian brain development. However, use of TS as a model for X chromosome haploinsufficiency is complicated by karyotypic mosaicism, background genetic heterogeneity and ovarian dysgenesis. Therefore, to better isolate X chromosome effects on brain development and identify how these overlap with normative sex differences, we used whole-brain structural imaging to study X-monosomic mice (free of mosaicism and ovarian dysgenesis) alongside their karyotypical normal male and female littermates. We demonstrate that murine X-monosomy (XO) causes (i) accentuation of XX vs XY differences in a set of sexually dimorphic structures including classical foci of sex-hormone action, such as the bed nucleus of the stria terminal and medial amygdala, (ii) parietal and striatal abnormalities that recapitulate those reported TS, and (iii) abnormal development of brain systems relevant for domains of altered cognition and emotion in both murine and human X-monosomy. Our findings suggest an unexpected role for X-linked genes in shaping sexually dimorphic brain development, and an evolutionarily conserved influence of X-linked genes on both cortical and subcortical development in mammals. Furthermore, our murine findings highlight the bed nucleus of the stria terminalis and periaqueductal gray matter as novel neuroanatomical candidates for closer study in TS. Integration of these data with existing genomic knowledge generates a set of novel, testable hypotheses regarding candidate mechanisms for each observed pattern of anatomical variation across XO, XX and XY groups.

KEYWORDS:

Aneuploidy; Brain development; Sex chromosomes; Sex differences

PMID:
23891883
PMCID:
PMC4838041
DOI:
10.1016/j.neuroimage.2013.07.052
[Indexed for MEDLINE]
Free PMC Article

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