trisomy 13

i was wondering if trisomy 13 is an inherited disorder or not. I'm 18 weeks and have been give a 0 % chance of my baby surviving, they are about 90% thinking the defects are caused by this disorder but the other 10% is because there is also some defects in the placenta. Everything I read about trisomy 13 conflicts about is it is heritary or not

[Lisa Kessler, MS, CGC]

It is very difficult when something unexpected comes up during a pregnancy, and I am sorry that you are experiencing this now.  

As you have read, trisomy 13, also called Patau Syndrome, occurs in about 1 in 5,000-10,000 live born infants.  Trisomy 13 is generally caused by an extra copy of chromosome #13 (three copies of chromosome #13).  Typically, we have 2 copies of each of our chromosomes.

It is very unusual for a family to have a second child with Trisomy 13.  This can occur when a baby has Trisomy 13 due not to a complete extra copy of chromosome 13, but rather due to a rearrangement of piece of chromosome 13 with another chromosome. This is called a translocation which can sometimes run in families.  However, full trisomy 13, which is the more common type of trisomy 13, does not usually run in families.  

It may be helpful to meet with a genetic counselor to review the results of your testing.  A local genetic counselor can be found through the NSGC’s website.  Best wishes to you.    

[beishuizen91]

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