holoprosencephaly type 4

holoprosencephaly type 4

A type of holoprosencephaly (OMIM:236100), which is the most common structural anomaly of the brain, in which the developing forebrain fails to correctly separate into right and left hemispheres, often accompanied by a typical facial appearance. 
Molecular pathology
Caused by defects of TGIF1, which encodes a member of the three-amino acid loop extension (TALE) superclass of highly conserved transcription regulators that may participate in transmitting nuclear signals.