neural tube defect
definition of neural tube defect
1. a disorder in which the brain, spinal cord, or the tissues protecting the brain or spine do not develop properly during pregnancy. Examples of neural tube defects include anencephaly (most of the skull and brain are missing), spina bifida (part of the spine may be on the outside of the body), and encephalocele (part of the brain is on the outside of the skull). It is a common cause of infant death and disability.1