Holoprosencephaly 2, also known as hpe2, is related to holoprosencephaly 6 and holoprosencephaly 1, and has symptoms including seizures An important gene associated with Holoprosencephaly 2 is SIX3 (SIX Homeobox 3). Affiliated tissues include brain and pituitary, and related phenotypes are global developmental delay and hypotelorism