Chances of having another baby with Trisomy 13

my daughter was diagnosed with FT13 ten days after birth. I had several level 2 ultrasounds done, however the prognosis was adult polycystic kidney disease. I did get a second opinion and the same prognosis was indicated. The geneticist also saw a clubbed foot, but reassured me that this was in no way related to a syndrome.They told me an amnio wasn´t necessary because it was quite evident that this was what we were dealing with.

My daughter passed away 2 months and 15 days later. Oh, and she didn't have PKD. No cysts in her kidneys. Left completely normal and the right slightly larger. Which was hard to accept, in the first place, since neither one had a family history of it. Anyone can imagine how heartbreaking this was for our family. We weren´t prepared for it and to a certain extent I take responsibility for not being in control.

Question: I am 34 now and would like to try once more. I do have a healthy little 3 yr old and according to the karotype it was not inherited. What are my chances of having something similiar occur if I give birth at age 35/36? I'm currently taking folic acid, but is there something else I could do?

Thank you for any info you can provide me with.

[Lisa Kessler, MS, CGC]

I am so sorry for the loss of your daughter.  It sounds like an extremely difficult situation for you and your family.  

As you know, 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.  I am assuming from your description of “FT 13” you mean full trisomy 13, in which case this is the more common type of trisomy 13, which usually does not run in families.  

Your actual risk for your pregnancy to be affected with a chromosome abnormality is dependent on how old you will be when you deliver. For example, if you will be 35, it is estimated at about 1 in 204, if you will be 36 it would be about 1 in 164.
Prenatal diagnosis with CVS or amniocentesis is an option for you in a future pregnancy.   Prenatal testing for birth defects is complex and quite personal.  If you are interested in learning more about the risks and benefits of these procedures, it may help to meet with a genetic counselor.  You can find a genetic counselor through the NSGC (National Society of Genetic Counselors) website.  

[Quett]

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