Holoprosencephaly occurs in 13q deletion syndrome (ZIC 2), 18p deletion syndrome (TGIF1), Smith Lemli Opitz (SLO, DHCR7), Hartsfield syndrome (FGFR1), Steinfeld (CDON or variants), Culler Jones (GLI2), hydrolethalus (HYLS1 and KIF7) and Pallister-Hall (GLI3). Here, TGIF1 is linked to holoprosencephaly.