Trisomy 18

Also known as: Edwards syndrome, chromosome 18 duplication

What is trisomy 18?

Trisomy 18 is a chromosome disorder that is present at birth. Patients with the condition have a third copy of chromosome 18 in their cells, which leads to a variety of lifelong symptoms ranging from intellectual disability to heart defects, a small and abnormally shaped head, low birth weight, clenched and overlapping fingers and more. Some people only have some cells with an extra chromosome 18, which is known as mosaic trisomy 18.

What causes trisomy 18?

Trisomy 18 is a genetic mutation that occurs when the fetus is growing before birth. What causes it to occur is usually not known. Trisomy 18 can be inherited from parents in some instances, but most cases of trisomy 13 are not inherited and occur at random.

What are the symptoms of trisomy 18?

Trisomy 18 can cause a wide range of symptoms, many of which are present at birth. They can include:

  • Severe intellectual disability
  • Heart defects
  • Low birth weight
  • Small and abnormally shaped head
  • Small jaw and mouth
  • Clenched fists
  • Overlapping fingers

These are just a few of the many symptoms that can occur.

How can trisomy 18 affect children?

Trisomy 18 occurs in one out of every 5,000-6,000 births. When it does occur, it impacts children starting before they are born and is a lifelong condition.

What are trisomy 18 treatments?

Sadly, the symptoms of trisomy 18 are often severe, and most children do not survive past the first two weeks of life. Fewer than 10 percent survive for longer than a year. Children with less severe symptoms will need continuous care and treatment for the complications of the disease. This includes regular childcare visits, immunizations, screenings, treatments and guidance for the complications of the disease. Support groups are also helpful for parents of children with trisomy 18.

Reviewed by: Gwen E Erkonen, MD

This page was last updated on: July 01, 2024 04:08 PM