Anencephaly is a condition that hinders normal brain and skull bone development, according to Genetics Home Reference. During the first couple of weeks of embryonic development, the neural tube that develops into the central nervous system may fail to close, resulting in anencephaly.
When the neural tube fails to close properly during embryonic development, it exposes the central nervous system to the amniotic fluid in the womb, leading to the degeneration of the system tissue, explains Genetics Home Reference. Consequently, anencephaly patients lack the cerebrum and cerebellum, which are responsible for hearing, thinking, vision, movement coordination and emotion. The exposure also hinders the formation of the skull bones. These malformations cause severe nervous system conditions, which may lead to fetal death and miscarriage.
The risk factors of anencephaly can either be genetic or environmental, notes Genetics Home Reference. Changes in the genes, such as methylenetetrahydrofolate reductase that aid in processing vitamin folate, may result in vitamin deficiency that predisposes the neural tube to anencephaly. Vitamin folate deficiency may also be caused by lack of folic acid in the diet of a woman who is yet to get pregnant. Other conditions such as diabetes mellitus and obesity may also expose the fetus to anencephaly.