Neural tube defects are a group of severe birth defects in which the brain and spinal cord are malformed and lack the protective skeletal and soft tissue encasement.

Incomplete formation and protection of the brain or spinal cord with bony and soft tissue coverings during the fourth week of embryo formation are known collectively as neural tube defects. Lesions may occur anywhere in the midline of the head or spine. These defects are among the most common serious birth defects, but they vary considerably in their severity. In some cases, the brain or spinal cord is completely exposed, in some cases protected by a tough membrane (meninges), and in other cases covered by skin.

Most neural tube defects (80-90%) occur as isolated defects. Neural tube defects of this variety are believed to arise through the combined influence of genetic and environmental forces...