Life With An Extra Chromosome (3 Types of Down syndrome)

For Down Syndrome Awareness Month, I've been posting facts on Facebook about Down syndrome. (I guess what the facts were about was quite obvious... it wouldn't make much sense to post facts about growing a garden during Down Syndrome Awareness Month.)

But, for the ga-zillions of you who are "Facebookers," you know that there is a limit on the number of words you can type in one status update. (Not exactly convenient for someone like me who.... well, likes to talk.)

I wanted to share with you all something that very few people know...

There are actually three different kinds of Down syndrome.

Crazy, huh?

1. Non-disjunction Down syndrome (Trisomy 21) occurs in 95% of all babies born with Down syndrome. This type of Down syndrome occurs because of an "error" * in cell division. The "error" happens either before or at the time of conception. What happens is that a pair of the 21st chromosomes (in either the egg or the sperm) do not separate properly. This extra chromosome is then found in every cell in the body. (This is the type Rylee has.)

* I got this description from a reputable website, however I am not thrilled with the word "error." The dictionary defines "error" as "a mistake." I definitely don't see this as an "error." I think chromosomes know exactly what they're doing... *smile*

2. Mosaic Down syndrome occurs in about 1-2% of all babies born with Down syndrome. In this type of Down syndrome, the "error" in separation of the 21st chromosome occurs in one of the first few cell divisions after fertilization. This causes the fetus to have some cells with 46 chromosomes (the typical number) and some with 47. So, not every cell contains an extra 21st chromosome. (There is no rhyme or reason as to which cells have the extra chromosome.) Because not all cells contain the extra chromosome, individuals with Mosaic Ds may not have all of the physical characteristics that are typical with Non-disjunction Ds.

3. Translocation Down syndrome occurs in 3-4% of babies born with Down syndrome. In this type of Down syndrome, a part of chromosome 21 breaks off and attaches itself to another chromosome (often chromosome #14.) This causes all cells in the body to have the extra piece of the 21st chromosome. When a child is born with this type of Ds it could mean that one of the parents is carrying chromosomal material that is unusually arranged, but this is not always the case.

So there you have it... 3 different types. Are you feeling smarter now?

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Rylee - 1 month old

When Rylee was younger, I remember some people asking questions that eluded to the possibility of there being different degrees of Down syndrome. A little part of me wanted to giggle and say, "Well, are you a little bit female or all female?" (Oh... bad example. In this day and age there may actually be individuals that are just a little bit female, but I'm not going there.) What I mean to say is that either you have Down syndrome or not. There are no degrees... no levels... no "a little bit of Down syndrome." You have it or you don't. Period.

Others have asked me along the way if Rylee is "high-functioning." This is another interesting question. Actually, it's a question that I have thought about more over the years, and I'm not a fan of it. People usually ask this question if they perceive the child to be doing things "well"... maybe the child's speech is understandable to them; maybe the child is accomplishing things that they assume children with Ds have difficulty with. The question is asked in such a way that, if the child is in fact "high functioning," that is such a good thing. So, on the contrary, if the child is not "high functioning" then it is a bad thing.

Do we really need to give our children another label? Rylee isn't "high-functioning." She isn't "low-functioning." She functions like Rylee.

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Rylee - 3 months old

Think about the wide range of abilities and physical characteristics of "typical" individuals. Individuals with Down syndrome are the very same way. The diagnosis of Down syndrome doesn't mean every child will be the same... even if they have the same type of Down syndrome, there are still differences.

Just like I said in one of Rylee's letters, if you want to know what an individual with Down syndrome is like, don't assume you know -- get to know them.

I think you will be quite happy you did.