Craniorachischisis is the most severe type of neural tube defect in which both the brain and spinal cord remain open; both anencephaly and spina bifida (from the cervical region to the lumbar or sacral region of the spine) are present. Fetuses with craniorachischisis often miscarry during pregnancy or die shortly after birth. The cause is thought to be multifactorial, which means that a combination of genetic and non-genetic factors play a role.

Craniorachischisis is the most severe type of neural tube defect, in which almost the entire brain and spinal cord remain open. This means that an affected fetus has both anencephaly and spina bifida. Other birth defects and underlying conditions have been reported in affected individuals, including trisomy 18 and pentalogy of Cantrell. Fetuses with craniorachischisis often miscarry during the pregnancy or die shortly after birth.

MTHFR gene has been associated with NTDs. More recent studies have suggested that mutations in the CELSR1 and SCRIB genes may be associated with craniorachischisis specifically.