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Trisomy 18 is a genetic disorder in which a person has a third copy of material from chromosome 18, instead of the usual two copies.
Trisomy 18 is a relatively common syndrome. It is three times more common in girls than boys. The syndrome is caused by the presence of extra material from chromosome 18. The extra material interferes with normal development.
Examination of the pregnant woman may show an unusually large uterus and extra amniotic fluid. An unusually small placenta may be seen when the baby is born.
Other signs include:
There are often signs of congenital heart disease, such as:
Tests may also show kidney problems, including:
Treatment of children with Trisomy 18 is planned on a case-by-case basis. Which treatments are used depends on the patient's individual condition.
Half of infants with this condition do not survive beyond the first week of life. Some children have survived to the teenage years, but with serious medical and developmental problems.
Complications depend on the specific defects and symptoms.
Genetic counseling can help families understand the condition, the risks of inheriting it, and how to care for the patient.
Tests can be done during pregnancy to determine if the child has this syndrome.
Genetic testing is recommended for parents who have a child with this syndrome who want additional children.
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