What Is Cyclopia In Babies? Causes, Risks, And Diagnosis

Cyclopia in babies is a rare congenital abnormality that occurs due to failure of the forebrain (prosencephalon) to properly divide into left and right hemispheres during the embryonic development of the fetus. Other names for this condition are alobar holoprosencephaly or cycloprocephaly.

This condition is reportedly seen as 1.05 in 100,000 births (including stillbirths) of infants (1). It is possible to detect cyclopia during the early prenatal scan, as forebrain cleavage occurs anywhere between 18 and 28 days of gestation.

A baby with cyclopia may present characteristic clinical features such as proboscis (a tube-like growth protruding from the forehead) above the eye, single eye, or partially divided eye in one orbit. Cyclopia is an extreme malformation of the disorder called holoprosencephaly.

Causes Of Cyclopia In Babies

The exact cause of cyclopia is unknown. Mutations in various genes involved in the central nervous system (CNS) development may cause it (1). Sonic Hedgehog protein, a key signaling molecule involved in embryonic development, is often found to be mutated in some cases of cyclopia and other types of holoprosencephaly. However, many cases may not have an obvious cause.

Risk Factors For Cyclopia

Although the cause is unknown, possible risk factors for cyclopia and other types of holoprosencephaly are identified. The following fetal factors may increase the risk of cyclopia in babies (2).

• Patau syndrome or trisomy 13 is a chromosomal anomaly often associated with cyclopia. In this condition, extra genetic material on chromosome 13 disrupts normal organ development.
• Smith-Lemli-Opitz syndrome (SLOS) is characterized by slow growth before and after birth. It may cause multiple malformation syndromes, including facial malformations and microcephaly.
• Female gender of the baby.

The following maternal factors may also contribute to the development of cyclopia.

• Multiple pregnancies, especially with twins
• Gestational diabetes
• Previous unexplained pregnancy loss (miscarriages)
• Alcohol consumption
• TORCH infections and other trans-placental infections
• Nicotine exposure (cigarette smoking)
• Lithium exposure
• Anticonvulsant use during pregnancy
• Retinoic acid exposure during pregnancy
• Certain birth control pills to a lesser extent
• Exposure to cyclopamine, a toxin found in plants, such as corn lily, believed to cure morning sickness during pregnancy

Not all babies exposed to these factors develop cyclopia. Some may be born with other health issues or born perfectly healthy. However, it is always recommended to minimize risk by avoiding exposure to these factors.

Associated Features In Cyclopia

The following features are seen in babies born with cyclopia (1).

• Microcephaly (small head) due to an underdeveloped brain
• Absence of nose
• The single central eye is seen in true cyclopia (one-eyed baby)
• Synophthalmia is where two eyes are fused and forms a single eye in the middle of the forehead
• Proboscis (elongated appendage on the head) above the eye
• The underdeveloped mouth may appear as soft tissues with an opening
• Micrognathia is a very small lower jaw

Renal (kidney) dysplasia, polydactyly (extra fingers or toes), and omphalocele (protruding abdominal organs outside the abdominal wall) are common extracranial malformations seen in cyclopia.

Diagnosis Of Cyclopia

Cyclopia can be diagnosed during prenatal ultrasound. Prenatal scans at 11 and 13 weeks of gestation can enable early detection of cyclopia. The following features on ultrasound images indicate the condition.

• Monoventricle
• Lack of the third brain ventricle
• Severe facial deformities
• Absence or hypoplasia (underdeveloped) of certain parts of the brain, such as corpus callosum and fissures
• Changes in the arrangement of cerebral arteries

Chromosomal analysis is often done after birth since the information can be useful for parents’ genetic counseling.

Life Expectancy In The Case Of Cyclopia

Cyclopia is the most severe form of alobar holoprosencephaly. The prognosis is grave since it is not a condition compatible with life (3). Death may occur in the uterus or within a few hours after birth.

The maximum recorded lifespan of a baby with cyclopia is one day. Therefore, if cyclopia is present, doctors may suggest termination of pregnancy in the early weeks of gestation, depending on the country’s legislation.

Infographic: Limit The Risks

A few factors could increase the risk of congenital disabilities such as cyclopia. While you may not be able to control genetic risks, exposure to certain substances can be restricted. The infographic below lists such harmful substances that could increase cyclopia risk in fetuses. Save and share this infographic with expectant mothers or those trying to conceive and be a part of their healthy pregnancy journey.

References

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Reviewer

Dr. Neema ShresthaMD

     

Dr. Neema Shrestha is a pediatrician with a special interest in the field of neonatology. She has an overall experience of five years working in the field. Currently working in Kathmandu, Nepal, she completed her MBBS from Kasturba Medical College, Manipal in 2008, Diploma in Child Health from D.

Read full bio of Dr. Neema Shrestha