TGIF1 and holoprosencephaly: The strongest local genetic correlation supporting this finding was observed between the total mean thickness of the CC and the rostral anterior cingulate thickness on TGIF1. As TGIF1 is implicated in holoprosencephaly (i.e. where the brain fails to develop two hemispheres), forebrain development via alterations in the Sonic Hedgehog (SHH) pathway, and disruption of axonal guidance via chemoattractive mechanisms84,85, these results provide a potential genetic localization for functional follow-up.