MedGen

A rare disorder characterized by the partial separation of the cerebral hemispheres. It is associated with mutations in the SIX3 gene. [from NCI]

Holoprosencephaly (HPE) is the most commonly occurring congenital structural forebrain anomaly in humans. HPE is associated with mental retardation and craniofacial malformations. Considerable heterogeneity in the genetic causes of HPE has been demonstrated (Ming et al., 2002). For general phenotypic information and a discussion of genetic heterogeneity of holoprosencephaly, see HPE1 (236100). [from OMIM]

A rare disorder caused by mutations in the TGIF gene mapped to chromosome 18p11.3. It is characterized by semilobar holoprosencephaly, hypotelorism, and ptosis. [from NCI]

Lack of the cartilage of the nasal septum. [from HPO]