It is a rare type of neural tube defect where the head is bent backwards and spine is deformed. Infants affected are short with a proportionally large head and an absent neck. The head is usually facing upwards.
The infants will not live for very long and the odd distortion of the body causes a potential risk for the mother during childbirth. It is usually accompanied by other cephalic defects such as anencephaly, cyclopia and otocephaly.