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Edwards syndrome is a genetic condition caused by a chromosomal abnormality. This serious condition, which occurs in about 1 out of 5,000 births, has dramatic effects on growth and development. Edwards syndrome affects many parts of the body and has no cure. The type with which a baby is born dictates the severity of the outcome, though, sadly, Edwards syndrome is usually fatal.

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Trisomy 18

Edwards syndrome is caused by an extra copy of chromosome 18. Human cells typically have 23 pairs of chromosomes, molecules that carry the genetic material inherited from the parents. That means there are typically two copies of chromosome 1, chromosome 2, and so on. People with Edwards syndrome have a third copy of chromosome 18. The issue is also called trisomy 18.

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Causes of Edwards Syndrome

Most cases of Edwards syndrome are the result of random events during the creation of reproductive cells. An error in cell division, nondisjunction, causes the formation of a reproductive cell, such as a sperm or egg cell, with an extra copy of chromosome 18. Edwards syndrome is usually not hereditary and is not caused by any action taken or not taken by the parents before or during the pregnancy. Older parents are slightly more at risk of having a baby with this condition.

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Three Subtypes

There are three subtypes of Edwards syndrome, each with a different cause and possible outcomes.

  • Full Trisomy 18: Every cell in the body has the extra copy of chromosome 18. Almost all cases of Edwards syndrome, around 95%, are this subtype.
  • Mosaic Trisomy 18: The extra copy of chromosome 18 is present in some cells, but not in all of them.
  • Partial Trisomy 18: This subtype, where there is only one section with an additional chromosome 18, is the only type that can develop due to inheritable factors. This can happen when the extra part becomes attached to another chromosome during cell division. Consequently, the person has two normal copies of chromosome 18 and a third partial copy.
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Widespread Effects on Development

Extra genetic material from chromosome 18 causes problems with development that affect many parts of the baby's body, both during gestation and after birth. Common issues include problems with the heart, kidneys, and digestive system. Children with Edwards syndrome often have delayed growth, with small jaws and heads.

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Distinctive Physical Characteristics

Each child with Edwards syndrome has a unique response to the extra genetic material, though many share some of the same physical characteristics, including

  • Strawberry-shaped head
  • Clenched hands with overlapping fingers
  • Small jaw
  • Small head
  • Low-set ears
  • Rocker-bottom feet
  • Overall small size due to delayed growth
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Edwards Syndrome Diagnosis

Edwards syndrome is usually diagnosed during pregnancy. Typically, the first screening occurs between 10 and 14 weeks. A blood test or ultrasound are the first steps to check for this syndrome and other developmental disorders. If initial testing shows concerns, the parents may elect to have another test, which will require a sample of the baby's DNA. Medical professionals obtain the DNA using chorionic villus sampling or by amniocentesis.

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Confirming the Diagnosis

Once the lab has extracted DNA from the cell sample, the next step is to make a karotype, a picture made by isolating, staining, and photographing the chromosomes under a microscope. A visible third copy of chromosome 18 in the karotype confirms the diagnosis of Edwards syndrome.

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Treatments for Edwards Syndrome

There is no cure for Edwards syndrome. Treatments vary depending on the specific challenges the baby is facing. For example, children with a heart defect may need surgery to repair it, while those with digestive issues may require a feeding tube. Depending on the severity of the issues, the baby may need hospital care. If the case is less severe, parents may be able to provide care at home.

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Outcomes for Edwards syndrome

Because Edwards syndrome affects so many body systems and causes life-threatening medical problems, many children die before birth or within their first month. However, five to 10% of children with trisomy 18 will live past their first year. Though they will often be developmentally delayed and may have severe intellectual disabilities, these children can still thrive in a supportive environment.

Support for Families of Children With Edwards Syndrome

It can be difficult to learn that your child has Edwards syndrome. Fortunately, several organizations provide information, resources, and other support. A few examples are the Trisomy 18 Foundation and SOFT, both of which bring together families affected by trisomy 18 and raise awareness about the disorder.

Disclaimer

This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.