Born without a brain: Anencephaly

Ever heard of babies without brains? This sounds very gruesome and bizarre, but unfortunately it does happen in this world. This birth defect is called anencephaly. Although such a birth defect is not common, it is important that you as an expectant mother do everything you can to prevent such heartbreaking births. Table of contents:

  • What is Anencephaly?
  • Characteristics and symptoms
  • Diagnose
  • Causes
  • Prognosis and treatment
  • Prevention

 

What is Anencephaly?

Anencephaly is a cephalic disorder that results from a defect in a neural tube in which the head of the neural tube does not close properly. This usually happens between the 23rd and 26th day after conception. When the neural tube does not close properly, the underdeveloped brain and spinal cord are exposed to the amniotic fluid. This causes the nervous system to break down. The prevalence in the general population is 0.1%, so it is a rare condition. Research shows that anencephaly is more common in girls than in boys. Anencephaly comes from the Greek and literally means no brain . Despite this name, it is not always the case that the entire brain is missing, often the cerebrum containing the cerebral hemispheres, including the neocortex, is missing. The neocortex is responsible, among other things, for human cognition.

Characteristics and symptoms

The main feature of this birth defect is that the defect in the neural tube results in the absence of most of the brain ( cerebrum ), skull and scalp. Some babies are born with only a brain stem. The remaining part of the brain is often not covered by bone or skin, so it can be seen directly. In addition, the babies are often blind, deaf, unconscious and unable to feel pain. These babies will not be able to gain consciousness because they are missing the part of the brain normally responsible for consciousness. What can occur, however, are reflexive actions such as breathing and reactions to sounds and touches. They also often suffer from heart defects, skeletal deformities, abnormalities in the urinary system and the digestive system and the babies sometimes also have a cleft lip. Many of the pregnancies in which the fetus has a defect in the neural tube end in miscarriage.

Diagnose

Anencephaly can often be diagnosed before birth. This is done through ultrasound examination, fetal MRI, water amniocentesis and blood tests. These procedures usually take place between the 14th and 18th week of pregnancy. Anencephaly is divided into three subtypes:

  1. Meroanencephaly : This is a rare form of anencephaly characterized by malformed skull bones, a defect in the skull and a protrusion of the skull known as a cerebrovasculosa area . This cerebrovasculosa area is a portion of abnormal, spongy vascular tissue mixed with glial tissue.
  2. Holo-anencephaly : This is the most common type of anencephaly in which the brain is completely absent
  3. Craniorachischisis : this is the most severe form of anencephaly in which, in addition to skull abnormalities, there are also abnormalities in the spine and exposure of nerve tissue. About 1 in 10,000 babies in the United States are still born with the defect.

 

Source: National Center on Birth Defects and Developmental Disabilities, Wikimedia Commons (CC0)

Causes

The causes of anencephaly are still disputed. In general, it is known that neural tube defects have no hereditary background. About 90% of parents have no family history of neural tube defects. However, there is indirect evidence that this condition has a hereditary factor: studies have shown that if a woman has (had) a child with a defect in the neural tube (such as anencephaly), there is a four to five percent chance that the next child can also have a neural tube defect. If the parents have had two babies with anencephaly, the chance increases to ten to thirteen percent. A mutation in a certain gene can also be a cause of the defect. More research needs to be done into this. However, research has already found an association between the CART1 gene and anencephaly. It is also assumed that the MTHFR gene influences the risk of developing a neural tube defect.
It is also known that women who take certain medications for epilepsy and women who have insulin-dependent diabetes have an increased risk of having a child with a neural tube defect. High and prolonged exposure to toxic substances such as lead, chromium, mercury and nickel can also cause anencephaly. Obesity and exposure to high temperatures during early pregnancy (such as fever or use of a sauna) also increase the risk of anencephaly. In addition, an excess of vitamin A ( hypervitaminosis A ) also appears to increase the risk. Latin American women also have an increased risk of having a child with anencephaly, but it is still a mystery why this is the case.

Prognosis and treatment

There is no cure or standard treatment for anencephaly. Most babies with this birth defect do not survive and the prognosis is almost always death. Most babies are stillborn (in 75% of cases) and if the child is not stillborn, it usually dies from cardiac arrest within a few hours or days. These are often not resuscitated, because the chance of survival is very small and the babies could never achieve consciousness. If the child is still alive, it is often treated in a clinical practice where the child receives hydration, nutrition and comfort measures. However, this is considered medically pointless by some doctors and medical ethicists, just like artificial respiration, drug treatments such as antibiotics and surgery.
However, there are some exceptions of babies who have survived anencephaly longer than average. Stephanie Keene from the United States lived with anencephaly for two years and 174 days, Vitoria de Cristo who was born in Brazil also survived the birth defect for more than two years and Nickolas Coke from Colorado lived with anencephaly for three years and eleven months.

Prevention

When women are at increased risk of having a child with a neural tube defect, genetic counseling is offered to discuss available testing. This way, parents can know in advance the risk of having a child with anencephaly. To reduce the risk of a neural tube defect, women of childbearing age can add folic acid to their diet. Recent studies show that folic acid can significantly reduce the incidence of neural tube defects, but unfortunately cannot completely prevent them. It is therefore recommended that women who are planning to become pregnant (but are not yet pregnant) take 0.4 milligrams of folic acid (vitamin B9) per day. This can reduce the risk by 50-72%. It is very important to do this before pregnancy, because the critical period of neural tube formation is often over when one first realizes that the woman is pregnant. For women who have an increased risk of having a child with anencephaly, a higher dose of folic acid (4 milligrams per day) is often prescribed. You can take folic acid with supplements, but certain foods also contain a lot of folic acid, such as: kiwi, strawberries, melon, beets, asparagus, Brussels sprouts, spinach, avocados, beans, lentils and lettuce.

Actual photos of babies with anencephaly can be shocking. Click here if you still want to see the photos.

 

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