Facts about Trisomy

Facts about Trisomy

March is Trisomy Awareness Month. Many awareness months commemorate diseases the public is actually quite familiar with. Trisomy however, is a much less discussed medical concern. To commemorate this year’s theme of Trisomy Awareness Month,  “We are their Voice, They are our Heart,” we wanted to take a moment to share with you some basic facts you may not know about trisomy. 


What is trisomy? 


The majority of people have 23 pairs of chromosomes in most (if not all) of their cells. That is a total of 46 chromosomes. These chromosomes include unique DNA and other genetic material necessary to make up each individual. Some individuals have trisomy conditions. This means they have an extra chromosome in most or all of their cells, for a total of 47 chromosomes. 


What type of problems arise from trisomy? 


An extra chromosome can cause a variety of concerns ranging from mild intellectual and developmental disability, to severe physical problems. Rarely do trisomy conditions pass from one generation to the next. They are more likely  the result of a random error that occurs during cell division very early during development.


Trisomy can occur within any chromosome. The most well-known syndromes resulting are Trisomy 21 (Down Syndrome), Trisomy 18 (Edwards Syndrome) and Trisomy 13 (Patau Syndrome).


What are signs of trisomy during pregnancy?


Sometimes trisomies are diagnosed during pregnancy. These signs may include:


only one umbilical cord artery

too much amniotic fluid (polyhydramnios)

a smaller than expected placenta

an unusually inactive baby 

the baby measuring small

congenital defects such as cleft palate or heart irregularities picked up during ultrasound scans


How are trisomies diagnosed? 


During pregnancy the following tests may help your doctor discover a trisomy:


non-invasive prenatal testing (NIPT) 

maternal serum screening

ultrasound scans 

chorionic villus sampling



Although the news of your child having a trisomy may be difficult to accept, in many cases he or she can still live a fulfilling life. If you are in this position, talk to your CCMH Provider. He or she may recommend resources to help prepare you for this journey. 





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