another question about Down syndrome?

Down syndrome doesn't run in the family? It's just something to do with chromosomes before or at conception, something in the egg? So it means that father has nothing to do with carrying it? I looked online and everything is about women (age and etc)...

The real question is - if a guy had 2 children from one woman, (one of the kids has Down syndrome) and now he's expecting another child from another woman, what are the chances that baby will have it? first trimester test was negative.

I do understand that I'm not asking doctors, and yes, i tried to look for answers online.

thank you

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  • 1 decade ago
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    Down syndrome is based on an extra chromosome, chromosome 21. People without Down syndrome typically have 46 chromosomes, but because of the extra chromosome 21, people with Down syndrome have 47 chromosomes. People with Down syndrome have three copies of chromosome 21, which is why the disorder is also called Trisomy 21. The extra chromosome usually comes from the mother's egg.

    There are many factors when it comes to having a child with Down syndrome. Age being the most common. Women age 35 and older have a significantly higher risk of having a child with the condition. At age 30, for example, a woman has less than a 1 in 1,000 chance of conceiving a child with DS. Those odds increase to 1 in 400 by age 35. By 42, it jumps to about 1 in 60.

    Down syndrome is not hereditary, since it is a genetic mutation. People with Down syndrome may or may not have children with Down syndrome also. The odds are probably the same as in the general population.

    The chances of the baby having it are unlikely, because as I mentioned above, it is due to genetic mutation during conception. The fact that the guy has a child with Down Syndrome doesn't mean anything, it is not hereditary.

  • 1 decade ago

    From what I was able to find, Down's is definately a genetic disorder, which should mean that it's inheritable. But, it all depends on where the extra chromosone (#21) came from mom or dad.

    If the extra came from mom #1,then any of dad's subsequent children from mom #2 should not have risk of the disorder from him. It should be possible to have dad tested to see if he carries the extra chromosone. However, this is not the only manner in which Down's can occur and I can't tell if the other ways are inheritable or not.

    I put "causes down's syndrome" in the yahoo! search engine and at least 2 to 3 sites with some solid looking info came up. Hopefully, you'll be able to find enough information to get a fuller answer to your question.

  • 1 decade ago

    I have a Down Syndrome child and yes the sperm can cause it just as well as the egg. It is the age of either. It can be determined after the fact if it was egg or the sperm that caused the chromosome to change

  • lapis
    Lv 4
    1 decade ago

    If this is a question that directly pertains to you, you should consult a genetic councillor. There are many factors that determine risk. Down syndrome is a genetic condition, but does not appear to be hereditary (in most cases).

    Maternal age is the biggest risk factor, but I do remember reading some research that paternal age can also increase the risks.

    Link to some info : http://www.intellectualdisability.info/diagnosis/g...

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  • 1 decade ago

    It's all genetic. I was 28 when I gave birth to twin girls, one is typical, and the other has Mosaic down syndrome. I also have two other boys that are typical...and yes they are all from the same dad. Anything is possible, I think the chances of that happening are very low.

    Source(s): www.imdsa.com
  • Anonymous
    1 decade ago

    No, Down Syndrome is not inheritable - it's a random event during early pregnancy. If you are young and healthy your baby has no more chance of getting Down Syndrome than any other baby (about 1/1490).

  • The reasons for downsyndrome are, The age factor, Genetic defects (from both partners) or downsyndrome runs in the family.

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