Holoprosencephaly is a complex malformation of the cerebrum characterised by incomplete separation of the hemispheres of varying severity (Table 2), and is often manifested in associated facial anomalies that reflect the underlying brain malformation, especially in SHH associated holoprosencephaly although not with ZIC2, which shows a characteristic pattern of facial anomaly regardless of the brain malformation [53]. The gene discussed is ZIC2; the disease is holoprosencephaly.