Neural tube defects (NTDs) represent a common group of severe congenital malformations that result from failure of neural tube closure during early development. Their etiology is quite complex involving environmental and genetic factors. The most common and most severe NTDs include spina bifida (myelomeningocele) and anencephaly. Spina bifida is caused by failure of posterior neural tube closure resulting in exposure and/or herniation of the spinal cord. Anencephaly is caused by failure of anterior neural tube closure.
