Molecular screening of SHH, ZIC2, SIX3, and TGIF genes in patients with features of holoprosencephaly spectrum: Mutation review and genotype-phenotype correlations.
Large heterozygous deletions associated with human holoprosencephaly type 2 have been previously mapped to 2p21, opening the possibility that SIX3 could be involved in the development of midline structures of the head.
However, embryonic SIX3 expression is not limited to the eye field, and SIX3 has been found to be mutated in some patients with holoprosencephaly type 2 (HPE2), suggesting that SIX3 has wide implications in head development.