Six3 dosage mediates the pathogenesis of holoprosencephaly

Xin Geng, Sandra Acosta, Oleg Lagutin, Hyea Jin Gil, Guillermo Oliver*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Holoprosencephaly (HPE) is defined as the incomplete separation of the two cerebral hemispheres. The pathology of HPE is variable and, based on the severity of the defect, HPE is divided into alobar, semilobar, and lobar. Using a novel hypomorphic Six3 allele, we demonstrate in mice that variability in Six3 dosage results in different HPE phenotypes. Furthermore, we show that whereas the semilobar phenotype results from severe downregulation of Shh expression in the rostral diencephalon ventral midline, the alobar phenotype is caused by downregulation of Foxg1 expression in the anterior neural ectoderm. Consistent with these results, in vivo activation of the Shh signaling pathway rescued the semilobar phenotype but not the alobar phenotype. Our findings show that variations in Six3 dosage result in different forms of HPE.

Original languageEnglish (US)
Pages (from-to)4462-4473
Number of pages12
JournalDevelopment (Cambridge)
Issue number23
StatePublished - Dec 1 2016


  • Forebrain
  • Gene dosage
  • Holoprosencephaly
  • Mouse
  • Six3
  • Transcription factor

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology


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