Trisomy 18
Types of Edwards' syndrome
There are two main types of Edwards' syndrome.
Full form
Approximately 94% of babies with Edwards' syndrome will have thefull form, where every cell in their body has three copies of chromosome 18, instead of two. Mostbabies with this form will die before infancy.
Mosaic trisomy 18
About 5% of babies with Edwards' syndrome will have the extra copy of chromosome 18 in only some of their body cells. This less severe form of the disease is known as mosaic trisomy 18.
The severity of mosaic trisomy 18 depends on the type and number of cells that have the extra chromosome. Some babies may only be mildly affected, while some can be severely disabled.
Around seven in every 10 babies born with mosaic trisomy will live for at least a year and, in rare cases, babies with the condition may survive into early adulthood.
Medically Reviewed by a doctor on 21 Dec 2018
Introduction
Edwards' syndrome, also known as trisomy 18, is a serious genetic condition caused by an additional copy of chromosome 18 in some or all of the cells in the body.
What are the features and symptoms?
Babies with Edwards' syndrome can have a wide range of different problems. Physical signs of Edwards' syndrome include: a small, abnormally shaped head a small jaw and mouth long fingers that ove
How does Edwards' syndrome happen?
Edwards' syndrome is rarely inherited and the condition is not caused by anything the parents have done. The development of three copies of chromosome 18 usually happens randomly during the formation
Types of Edwards' syndrome
There are two main types of Edwards' syndrome. Full form Approximately 94% of babies with Edwards' syndrome will have thefull form, where every cell in their body has three copies of chromosome 18,
Testing for Edwards' syndrome during pregnancy
Pregnant women are offered screening for Edwards syndrome between 10 and 14 weeks of pregnancy to assess the chances of their baby having the condition. The screening test, known as the combined test
Information about your child
If your child hasEdwards' syndrome, your clinical team will pass information about him or her on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS). This helps scient
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