Wednesday, October 1, 2008

What is Down syndrome?

Down syndrome is the most common (but rare) genetic condition in which an individual has an extra copy of the 21st chromosome. A typical person has 46 chromosomes. People with Down syndrome have 47.

How does it happen? Here it comes, Biology 101 on Down syndrome.
All cells reproduce, either by mitosis, or meiosis.
Mitosis basically means the cell copies all of its contents (including it's 46 chromosomes) and then divides to produce 2 daughter cells.
Meiosis is the process in which reproductive cells divide. The egg and the sperm do not copy themselves, instead, they "split" in half, resulting in an egg having 23 chromosomes, and sperm having 23 chromosomes, to make a total of 46 when they come together.
In the case of Down syndrome, the 21st chromosome (typically in the egg) fails to "split," resulting in Trisomy 21 (three 21 chromosomes) when it is united with the sperm.

What causes Down syndrome? Why does an egg fail to disjunction on the 21st chromosome?
We don't know. There are only speculations. It is believed that maternal age is a factor (since women have ALL their eggs present even BEFORE they are born, and therefore, the older the women, the older the eggs).
I was 25 years old when I conceived Nichole. At that point, according to science, my chances were 1/2500.
Now, the following is MY OPINION. Please do not take it at face value.
I believe that the reason they think maternal age is a factor is because women 35 years and older have all the pre-natal tests done. Women 35 and younger, many many times chose not to have these tests. It makes sense that you will see ANY condition more often in a population that is routinely getting tested, as opposed to the population that selectively chooses to do so.
Eighty percent of babies with Down syndrome are born to women 35 and younger!

There are three different "types" of Down syndrome.
1) Non-disjunction Trisomy 21. The most common. 92% of people with Down syndrome have this type. It is basic meiosis where the 21st chromosome did not disjunction. (As I explained before)
2) Translocation Down syndrome. This is where one of the 21st chromosomes (either from sperm, or cell) is "broken." When it gets "broken" it "splits" in two, therefore, resulting in an extra 21st chromosome. This condition is believed to be hereditary. It is believed that 6% of individuals with Down syndrome have Translocation Ds.
3) Mosaic Down syndrome. Both the cell and the sperm are "typical." The non-disjunction occurs somewhere down the line of cell division resulting in an individual that has some "normal" cells, and some "Trisomy" cells. It does not matter how many "normal" cells there are, what matters is where those normal cells would be. For example, if the cells that form the eyes are not affected, an individual would sadly not display the beautiful almond shaped eyes characteristic of Down syndrome. Only 2% of individuals with Down syndrome have Mosaic Ds.
Some people believe this might also be hereditary. There is little to no difference in development of individuals with Mosaic Down syndrome as opposed to the other two types, UNLESS, it happened at the LAST STAGES of cell division. In some cases it is even possible for a person to have Mosaic Down syndrome and not know it.

What does Nichole have? Plain Non-disjunction Trisomy 21.

Are there different "levels" of Down syndrome? Or is there such a thing as a "low case" or "severe" case?
No, Down syndrome is Down syndrome. Development is directly linked to health issues.
Nichole would be considered "high functioning" (I know, she is a baby!) but she has had no serious health problems. Other babies that have serious health problems have a harder time "catching up."

Can doctors predict how well Nichole will do?
No. Nobody can. Nichole is Nichole. Most often doctors and other professionals talk about things that babies or individuals with Down syndrome can or cannot do. But, nobody can tell me what Nichole can or cannot do, she will show us what she is capable of, and she is doing amazing! She is her own person, and she will develop in her own rate, at her own time.

Is there any way to prevent Down syndrome?
Yes, there is a way that will guarantee that you will never have a child with Down syndrome. Do not have children :) Other than that, there is nothing that you can do or not do to prevent Down syndrome, or to cause Down syndrome for that matter. It is a God thing, it is a gift, and very few are fortunate and blessed to know this beautiful and amazing road.
God chose only a few of us to have these precious babies with a little extra something :) Even though I like to think it is because we are "special," I know for me it is because I needed much changing. It is a heart and life altering miracle. I am humbled and honored God chose me to be Nichole's mom.

Is Down syndrome a burden? ABSOLUTELY NOT! It is the greatest blessing our family has ever known. And Nichole continues to touch lives and hearts of those around her. There is nothing "less than perfect" about that.

Psalm 139
For you created my inmost being,
you knit me together in my mother's womb,
I praise you because I am fearfully and wonderfully made
your works are wonderful,
I know that full well

God does not make mistakes, especially, when there is an extra 21st chromosome :)


  1. Karina Guerrero3:12 PM

    OH Ellen! Thanks for letting us know much more from DS. I have a new doubt concerning your explaining:
    About Mosaic Trisomy 21, if there are "normal" cells and some "trisome" cells, the child is still considered DS Child? So, the child will develope almost all the problems from DS Child, but not not display some characteristis?

    And I have a new one: can you list all the health problems a DS child will have?

    Thanks! Huges and Kisses for you.

  2. Karina Guerrero3:17 PM

    OH, and I have a comment about an explanation, you said: "Eighty percent of babies with Down syndrome are born to women 35 and younger!", maybe that's because of the testing that is not done in that women, they don't know about having a DS child in uterus, so they don't have to decide to continue with pregnacy, and the 35+ women know already and have the option... Although I this is my opinion about that stadistics, I don't agree with abortion, and I still don't understand who had the STUPID IDEA of making that test, so you can decide to abort a "bad child" and accept only the "perfect children"...

  3. Hi There. I stumbled across your post through a google alert. I wanted to make an ammendment on your comments for mosaic Down syndrome.

    The majority of people with MDS do experience all the same developmental and congnitive delays as a person with Ds. The only difference is, they sometimes reach a milestone (like crawling and walking) a few months before a child with Ds.

    The exception to this rule is that children with MDS are more delayed in speech than their peers with Ds. And, we are finding a large majority of them with Apraxia. (a speech condition where the child began talking and then stops and uses no words or very few)

    Also, because people with MDS have a percentage of trisomy 21 cells in their body, they have the exact same risk for all the same health conditions as a person with Ds.

    And, as you said, many do not have the physical characteristics as one with Ds, or those characteristics are just not as prominent.

    Also, research suggests that up to 4% of those with Ds have MDS. In actuality, this number is much higher. There are many who are misdiagnosed with T21 who actually have MDS. In a recent independant study done by International Mosaic Down Syndrome Association 75 families were asked how they received their diagnosis. Of those 75--15% were first diagnosed with Trisomy 21 Down syndrome. This misdiagnosis and those who go undiagnosed would bring the number much higher than the outdated research states.

    I hope this has helped some to explain about mosaic Down syndrome.

    I am the mother of a 22 yr son with MDS....
    The president and co-founder of International Mosaic Down Syndrome Association....
    And, I write a daily blog on mosaic Down syndrome and Down syndrome called Mosaic Moments.

  4. Wow, a lot of good information. Sorry I didn't fill out any questions or leave a comment on your last post. I didn't know I had questions until I read the answers. :) Thanks for all your sharing, Ellen.

  5. Anonymous5:13 PM

    Hey Ellen, thanks for the blog, it is really nice to see how you and Andy and the rest of your family are doing! I guess I don't really have any questions, but I'll try to remember to keep you guys in my prayers. The Lord will bless you,

  6. Great post! Your girls are beautiful!

  7. Estimada familia,
    Gracias por un escrito tan bonito y una confianza tan tranquila y real en un Dios bueno. Es un regalo para Nichole haberla puesto en unos brazos tan amorosos. Damos muchas gracias a Dios por ustedes dos.
    Reciban nuestro cariño y cuenten con nuestro amor, respeto y oraciones.
    José y Lidia

  8. Hi Ellen
    Yes, you are more than welcome to include that information and all of our links! Please be sure to include the link to my blog as well as our link to IMDSA.

    Happy Birthday to Nicole!

  9. Oh yeah.... One more "tidbit"...
    There are actually FOUR different kinds of Down syndrome...

    Trisomy 21
    Mosaic Translocation


  10. Karina Guerrero8:58 AM

    HAPPY BIRTHDAY TO NICHOLE! I hope all of your family enjoy this beautiful and blessed day.
    I wish you the best and a lot of new blessings from God.


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