Anencephaly: Causes and Implications

Anencephaly is a severe congenital condition characterized by the absence of a major portion of the brain, skull, and scalp. This neural tube defect occurs during embryonic development, typically within the first few weeks of pregnancy.

Understanding the causes, implications, and diagnostic methods of anencephaly is critical for healthcare professionals and expectant parents alike.

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What is Anencephaly?

Anencephaly is a type of neural tube defect (NTD) where the neural tube fails to close properly. The neural tube is a precursor to the central nervous system, which comprises the brain and spinal cord. Due to this defect, infants born with anencephaly are usually missing large parts of the brain and skull. 

The Biological Mechanism

The neural tube's development is a complex process that begins in the third week of embryonic development. Normally, the neural tube closes completely by the 28th day after conception. 

However, in anencephaly, this closure is incomplete, leading to the brain tissue's exposure to amniotic fluid, which causes its degeneration.

Causes of Anencephaly

The exact anencephaly causes​ remain largely unknown, although several factors have been identified as potential contributors.

Genetic Factors: A family history of neural tube defects can increase the risk of anencephaly. Specific genes related to folate metabolism, like MTHFR, have also been linked to higher risks.

Nutritional Deficiency: Folate (vitamin B9) is essential for proper neural tube closure during early pregnancy. Lack of adequate folic acid intake before and during pregnancy significantly increases the risk of anencephaly.

Maternal Health: Conditions like diabetes in the mother can raise the likelihood of anencephaly. In addition, certain medications, such as anti-seizure drugs, and substances like alcohol and illicit drugs, can contribute to the risk.

Infections: Maternal infections during the first trimester, especially those affecting the neural development, may interfere with the baby’s brain development, leading to neural tube defects like anencephaly.

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Anencephaly Symptoms

Anencephaly symptoms is typically detected through prenatal imaging, as the infant exhibits very few external signs while still in the womb. Common symptoms include:

It’s important to note that the symptoms of anencephaly are not typically visible in the mother but are diagnosed via ultrasound or other imaging techniques.

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Implications of Anencephaly

Anencephaly in Adults

Although it’s extremely rare, there have been isolated cases of individuals who survive into adulthood with a form of partial anencephaly. In these rare cases, the individuals typically experience:

Anencephaly in Newborns

Newborns with anencephaly face significant challenges. These babies often die shortly after birth due to the lack of essential brain structures.

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Treatment for Anencephaly

Currently there is neither cure nor anencephaly treatment to reverse the effects of anencephaly. But treatment centers primarily around:

Prenatal Screening: Prenatal ultrasound may provide early diagnosis, allowing parents time to scope emotionally and logistically before the birth of a baby born with anencephaly. 

Palliative care: If the baby is born alive, palliative care is started to provide the baby with as much comfort as possible during the short life. 

Ethical Considerations: Families may be presented with options when it comes to anencephaly, continuing the pregnancy versus termination, based on personal, ethical and medical factors. 

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Prevention and Research

Efforts to prevent anencephaly focus primarily on addressing known risk factors and advancing research into potential causes and interventions.

Folic Acid Supplementation

The most effective preventive measure against anencephaly is adequate folic acid intake before conception and during early pregnancy. Public health campaigns promoting folic acid supplementation have significantly reduced the incidence of neural tube defects globally.

Ongoing Research

Research into the genetic and environmental factors contributing to anencephaly is ongoing. Advances in genomics and molecular biology hold promise for identifying new preventive strategies and therapeutic approaches.