Other genetic loci, such as GLI2, CDON (also known as CDO), FGF8, and DISP1 have also been associated with HPE or HPE-like phenotypes at lower frequency (Roessler et al., 2003, 2009; Bae et al., 2011; Hong et al., 2018). Here, FGF8 is linked to holoprosencephaly.