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Cyclopia: What Is It, Causes & Risk Factors

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Cyclopia is a visually startling congenital disorder. It causes a “cyclops-like” appearance, where the eyes don’t form into two distinct cavities, and the front part of the brain doesn’t separate. Instead, there is only one eye, and the nose is usually lacking.

This condition is not compatible with life.

What Is Cyclopia?

Cyclopia is a rare condition and form of holoprosencephaly where a baby is born with one eye at the center of the head. This occurs because the eyes have fused together as one. This severe defect is because of brain malformations during critical development stages in the womb.

The exact cause of cyclopia is unknown, but it causes a fetus to fail to develop two separate eyes during gestation. The front of the brain will lack a distinct right and left hemisphere. The nose is usually absent, or there is a distorted nonfunctional proboscis.

Newborns with cyclopia may also lack a mouth. If there is a proboscis, it is a malformed lump of tissue in place of a nose that is often centered and above the single eye.

Because the brain, eyes, and nose of a baby with cyclopia are so severely malformed and not adequately developed, live births do not survive long. Outside of the womb, the complications of cyclopia make it impossible to thrive hours or a day after delivery.

If doctors determine ‌a fetus has cyclopia before the gestation period is complete, they may offer medical termination, if legally available. For some births, it is only after a child is stillborn or visibly disfigured that medical professionals will diagnose cyclopia as the cause.

Causes of Cyclopia

Because cyclopia is so rare, there are not a lot of case studies to examine. However, there is ongoing research to investigate possible causes of this severe malformation of the brain, eyes, and nose.

There have been cases where a healthy mother with no history of substance abuse or genetic disorders gave birth to a child with cyclopia. Some babies with cyclopia have chromosomal abnormalities, but for others, there is no identifiable cause of the disorder.


Genetics may play a role in a newborn developing cyclopia in the womb. There are many other known congenital issues that arise during pregnancy or are visible at birth, which are all caused partly by genetic history.

Keep in mind that cyclopia is not a genetic disorder or disease. Cyclopia involves a severe physical deformity of the eye, brain, nose, and mouth that interferes with the body’s ability to survive.

Also, certain related disorders may coexist alongside cyclopia, including but not limited to the following:

  • Hartsfield syndrome
  • Smith-Lemli-Opitz syndrome
  • Pallister-Hall syndrome

Chromosomes Malformation & Disorders

For many cases of cyclopia, malformation and disorders of specific chromosomes are present. Following conception, as an embryo develops into a fetus, chromosomal problems can trigger severe issues.

Embryos may have some form of abnormality or damage from the start before fertilization and implantation. Ongoing research reviews the connection between environmental factors that may influence and cause common birth disorders.

According to research, a third of children born with cyclopia will show chromosomal abnormality. It is common for affected children to have three copies of chromosome 13. However, other chromosome defects or gene changes are also relevant.


Mothers who develop gestational diabetes or already have diabetes before becoming pregnant may have a greater chance of giving birth to a child with cyclopia or other birth defects. Uncontrolled diabetes during pregnancy may significantly influence a child’s development in the womb.

Diabetes impacts both the mother’s body and that of the fetus. DNA damage, oxidative stress, and altered cellular behavior may lead to newborns born with physical defects, and severe, non-genetic disorders.

Disorientation of Tissue & Cells During Formation

Because of environmental toxins, poor nutrition, existing health ailments, and genetic disorders, there may be tissue and cell formation problems during gestation. In the womb, defects occur when cells and tissue fail to communicate and develop normally.


Mothers must abstain from consuming alcohol or hazardous substances during their pregnancy. In one case, an alcoholic mother gave birth to a child with cyclopia. Research has repeatedly shown the risk of exposure to toxins and an increased risk of defects.

Toxins are not only present from the consumption of alcohol or drugs. Environmental factors can also induce defects and disorders in newborns. Teratogens can trigger or raise the chance of a child being born with health problems.

Some examples of teratogens include‌ the following:

  • Toxic chemicals
  • Alcohol and street drugs
  • Certain medications
  • Specific types of radiation
  • Viruses and bacteria

Ongoing studies connect exposure to toxins in the air, water, and soil with genetic alterations, damage, and stress that lead to newborns with health problems.

Also, animals who consume toxins from plants, like False-hellebore, may develop cyclopia.

Ongoing Research

Because cases of cyclopia are so rare, there are still a lot of lingering questions about the condition’s root cause. Research is ongoing into potential causes.

How Early Can Cyclopia Be Detected?

Cyclopia can often be detected through routine prenatal screening. With advancements in medical imaging, the condition may be identified as early as the first trimester. Here’s a more detailed look at how and when cyclopia can be detected:

  1. Ultrasound: A standard ultrasound performed during the first or second trimester of pregnancy can often identify the presence of cyclopia. High-resolution ultrasound, with the support of 3D imaging, provides an enhanced view of fetal anatomy, making it easier to identify severe structural abnormalities.
  2. Magnetic Resonance Imaging (MRI): In some cases, fetal MRI may be used to provide a more detailed view of the brain’s development, allowing healthcare providers to assess the condition more accurately.
  3. Genetic Testing: Though cyclopia is not specifically a genetic disease, chromosomal abnormalities may be linked to its occurrence. Genetic counseling and testing might provide further insights, especially if there’s a family history of congenital anomalies or if other risk factors are present.
  4. Professional Examination After Birth: In some instances, cyclopia may not be detected until birth, particularly in regions where access to prenatal care may be limited.

Early detection of cyclopia allows parents and healthcare providers to make informed decisions regarding the pregnancy. Though the condition is not compatible with life, understanding the diagnosis ahead of time may allow for careful planning and emotional preparation.

Risk Factors

The risk of a child being born with cyclopia is 1 in 100,000. Children with this congenital condition are typically born without a nose or mouth. Sometimes, the newborn may have a non-functioning proboscis above the eye.

Currently, there is no way to prevent or treat cyclopia. The condition may occur because of genetics, the mother’s pre-existing health conditions, environmental factors, or unknown reasons. Cyclopia happens to males and females equally, from all backgrounds and locations.

Generally, cyclopia will be detected on an ultrasound during standard prenatal care. Once diagnosed, a medical professional can help a patient to determine next steps.

Cyclopia FAQs

Can you survive with cyclopia?

No, cyclopia is not compatible with life. Most often, miscarriage or stillbirth occurs. If a live birth does happen, the baby will not survive for long, generally only a couple hours.

How do you get cyclopia?

There is no exact cause or reason ‌for a baby to develop cyclopia during gestation. Continuing research is ongoing to discover why cyclopia occurs. Cyclopia is incredibly rare.

How many babies are born with cyclopia?

Cyclopia is not a common congenital defect. Only 1 out of 100,000 newborns will have cyclopia, and this includes stillbirths.

What is the incidence of holoprosencephaly?

During embryo development, holoprosencephaly occurs in 1 out of 250 cases. For live births, the rate of incidents is 1 out of 16,000.

Is cyclopia a genetic disease?

Cyclopia may occur because of genetic disease or chromosomal defects, but it is not ‌a genetic disease. Cyclopia is a condition, and the direct cause is unknown. Adults with a high risk for congenital disease and related problems should seek medical testing to assess their personal risk if they choose to have a child.

Is cyclopia preventable or treatable?

There may be some hope of treating cyclopia in the future with continuing research and exploring human DNA. Currently, cyclopia is not preventable, and there is no treatment available.


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  2. Cyclopia Syndrome. (June 2014). BMJ Case Reports.
  3. Cyclopia: A Rare Condition With Unusual Presentation – A Case Report. (February 2015). Clinical Medicine Insights: Pediatrics.
  4. Environmental Disruption of Normal Development. (2000). Developmental Biology, 6th Edition.
  5. Diabetes, Oxidative Stress, and DNA Damage Modulate Cranial Neural Crest Cell Development and the Phenotype Variability of Craniofacial Disorders. (May 20, 2021). Frontiers in Cell and Developmental Biology.
  6. Are Chromosomal Disorders Inherited? MedlinePlus.
  7. Medical Genetics: How Chromosome Abnormalities Happen. University of Rochester Medical Center.
  8. Guide to Poisonous Plants. Colorado State University.
  9. Air Pollutants Linked to Higher Risk of Birth Defects, Researchers Find. (March 2013). Stanford Medicine.
  10. Mom’s Better Diet Could Mean Fewer Birth Defects. (August 2015). The University of Utah.
  11. Cell Disorientation by Loss of SHH-dependent Mechanosensation Causes Cyclopia. (July 2022). Science Advances.
  12. Pre-Existing Diabetes Can Increase Risk for Birth Defects. (December 2020). Centers for Disease Control and Prevention.
  13. Birth Defects in Pregestational Diabetes: Defect Range, Glycemic Threshold, and Pathogenesis. (April 2015). World Journal of Diabetes.
  14. Cyclopia Baby: Congenital Lethal Malformation: Rare Case Report. (July 2022). International Journal of Case Surgery Reports.
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