Anencephaly is a serious condition that impairs the development of the brain. It is caused by abnormalities that affect the neural tube, and is categorised as a neural tube defect.
The neural tube consists of a bundle of cells, which later develops into the spinal cord and brain. If the tube doesn’t close properly during the early stages of pregnancy, this exposes the cells to amniotic fluid, which triggers deterioration of the nerve tissue and results in severe structural abnormalities in the brain.
Almost all infants with anencephaly will die during pregnancy or during the first few hours after birth.
Anencephaly is also known as anencephalia, aprosencephaly and anencephalus.
How common is anencephaly?
Anencephaly is one of the most common defects of the neural tube. It is difficult to determine an exact number of cases, due to the fact that many cases end in miscarriage. However, it is estimated that this condition affects 1 in every 1,000 pregnancies.
What causes anencephaly?
Anencephaly is a very complex condition, and is believed to be caused by a mixture of genetic and environmental factors. There is still a degree of uncertainty as to the cause of many cases of anencephaly, although some factors have been identified.
Genetic mutations may be instrumental in the development of anencephaly and one gene that has been studied in depth is MTHFR, which is responsible for providing instructions for creating the protein used to process folate, vitamin B9 or folic acid. There is also evidence to suggest that a lack of folic acid could also increase the risk of anencephaly. Research suggests women that take folic acid supplements during pregnancy are less expected to give birth to a baby with a defected neural tube.
Additional risk factors may include obesity, exposure to very hot temperatures during pregnancy, diabetes and taking some forms of medication during pregnancy.
Is anencephaly inherited?
The majority of cases of anencephaly occur without any trace of family history. Although there are cases where anencephaly runs in families, evidence suggests that there is no obvious inheritance pattern. However, if you have had a child with anencephaly, the risk of having another child with the defect is slightly elevated.