I'm a carrier for down syndrome what are the chances my child may be born with down syndrome?

Question

I am a carrier of down syndrome, I am expecting my third child and do not know if I should have the baby tested for down syndrome. I have two healthy children that were never tested, but I also didn't know that I was a carrier of it until I became pregnant with this one. What are my chances of having a child with down syndrome since I am a carrier? I am worried about this baby...

Answer 1

I'm unsure what you mean that you are a "carrier" of Down syndrome.  While being a carrier is possible (albeit extremely unlikely), you would not know that unless you have had your own chromosomes analyzed.  People who are "carriers" of Down syndrome have what is called a Robertsonian translocation involving chromosome 21.  

Another poster said something to the effect of women under 35 not having the genetic material for Down syndrome - this is incorrect.  ANY woman, regardless of age, can have a baby with Down syndrome.  It happens when chromosomes do not split properly when the egg (or sperm) is formed and that egg (or sperm) ends up with an extra copy of chromosome 21.  This is called "nondisjunction" and the chance of it happening increases with advancing maternal age.

The comments about whether the baby's father is a carrier are also irrelevant - there are conditions (such as cystic fibrosis) where it matters whether both parents are carriers, but Down syndrome is not such a condition.  Most of the time it occurs, it is sporadic.

I am wondering if you had a blood test (quad screen/triple screen/AFP test) that gave a revised risk estimate for Down syndrome and the result was "screen positive."  If this is the case, then the test result should have given a specific numeric risk (1/100, 1/5000, etc) that your doctor should have told you.  Keep in mind these are only risk estimates and are not diagnostic results.  Again, if this is the case, and you are asking whether to have a test like amniocentesis to give you a yes-or-no answer, you should consider how important that information is to you, and what you would do with the results (whether positive or negative).

Good luck!

Answer 2

Since you have already had two healthy children, sounds like your chances are good to have another one. However, to determine the exact risk, you and your partner would need to see a genetic specialist of some type.

Answer 3

You should probably talk to a genetic counselor. They will provide you with the most accurate statistics and maybe even ease your mind!Your doctor didn't give you any statistics to go by when he told you that you were a carrier?

Answer 4

I'm not being rude, but I don't understand how you could be a "carrier" for Down Syndrome. Unless you are 35 or older, there is no genetic material in a person that will be carried through associating to Down Syndrome. It is a matter of chromosomal abnormality occuring when the egg is fertilized and begins to divide. Unless you are aged 35 or older, I wouldn't worry about it too much. The rate of Down Syndrome are:

Age 21... 1 in 1520

Age 35... 1 in 355

Age 40... 1 in 90

Age 43... 1 in 40

This is dependent on the woman's age, not the man's.

Answer 5

if the father isnt a carrier then the chances are slim. but what would getting the baby tested achieve anyway?

Answer 6

If you are actually a carrier of this rare type of DS, the odds are about 12% that you will pass it on to a child.

ace_gert is right about everything, and I'll just add that the fact that you had other children without DS is also irrelevant to the odds of having one with DS.

Answer 7

You'd need to get a karyotype done at a genetic specialist's office to know your chances.  

But, also know that often times, downs is not genetic.  It happens during cell reproduction and division as a result of nondisjunction...

Answer 8

does this baby have the same father as the other two if so it should be fine because if he was a carrier the other children would very likely have down syndrome but if you are concerned have an amniocentesis