31 for 21: Forms of Down Syndrome

The most common form of Down syndrome occurs either before or during conception, an "error" in cell division creates three copies of the 21st chromosome instead of the normal two.  Because of the third twenty-first chromosome, it is also known as Trisomy 21 (or T21 for short).  Any chromosome, or part of a chromosome, can be "triplicated" however, most of those "errors", do not allow a baby to make it to birth. Because of this, Trisomy21 is the most common genetic abnormality in live births. About 95% of people living with Down syndrome have T21. 

What many are unaware of is that there are two other forms of Down syndrome. 

1-2% of all people living with Down syndrome have a form called Mosaicism. In this type of Down syndrome the "error"in the separation of the twenty-first chromosome happens after fertilization. This causes the baby to have some cells with the typical amount of forty-six chromosomes and some cells with forty-seven; the extra being in the twenty-first chromosome. Because some cell are unaffected the child's abilities and capabilities may be greater than a child with the other two forms of Down syndrome. However, it depends on the ratio of the forty-six chromosomes to the forty-seven chromosomes.

The third form of Down syndrome is called Translocation. 3-4% of individuals who have Down syndrome have this form of it. Our Vada is one of those individuals. In this form of Down syndrome a piece of the twenty-first chromosome breaks off and reattaches itself elsewhere, usually onto the fourteenth chromosome. Translocation causes every cell to have an extra piece of the twenty-first cell. In Vada's case her extra piece practically reattached itself to its original strand. 


When a child is born with Translocation  it could mean that one of the parents is a carrier of a specific chromosomal material mater. Since I had two children prior to my marriage with Justin we knew that I was not a possibility. Parent who have the arranged chromosomal material will always produce a child who would have Down syndrome. To better prepare ourselves, my husband, Justin, had genetic testing done and after two very long weeks the test showed that he is not a carrier. Therefore the Translocation just happened and we don't mind it all. 


If you are interested the test done to determine what form of Down syndrome an individual has is called Karyotyping.

This is a copy of Vada's Karyotypes. If you look at number 21, her 21st chromosome, you can see that there is an arrow pointing to an empty spot. That's where her third, twenty-first chromosome would be if she had T21. However, that third little booger jumped to its neighbor and is actually sitting on top of what would have been the middle chromosome of the group. If you look carefully you can see that the first, twenty first has only one "dot" and the second has two. That second "dot" is actually Vada's piece or her third, twenty-first. Understand? I tried not to be confusing... When I first looked at these results I thought the arrow meant that since the piece wasn't there that they were saying she didn't have Down syndrome. Low and behold, she just has another form.

The truth is, regardless of what form of Down syndrome Vada may or may not have, her diagnosis is not a negative thing to our family. Vada is an important piece to our family puzzle and without her we would not be whole. She is loved, cherished, honored and respected. Like all children, she is proof of God's perfect works.

Location, Location

As most of you know Vada and I met with the Geneticist; Dr. Hoganson, yesterday. We had gone to see him because originally they thought that Vada had a condition called Methalmalomic Acid Anemia. Turns out she us has low B12, which is great, especially compared to the MMA. The low B12 is treatable.

Prior to this appointment we had gave gave Vada a weeks worth of daily B12 injections. Then they re-tested her levels and her B12 sky rocketed. So, now we are just going to monitor those levels to make sure she is doing alright. We also put her on Poly Vi Sol, which is a daily vitamin.

We kept our appointment with Dr H. just to be able to discuss any concerns or any other findings he may have had. The whole visit was quick and easy.

We also discussed my lab work that was done the week prior to this visit because we were concerned that I may have very low levels of B12 which was in return causing Vada to have the low levels. Turns out my B12 levels are low, but not too low. I also have low iron and my Thyroid is low as well. I wasn't really surprised since I have been mildly anemic since before my pregnancy with Vada and I have had Hypothyroidism since the birth of Kiliegh. All I need to do is take a better daily vitamin and bump up my Thyroid medications.

Before we left our meeting with Dr. H. I asked for a copy of Vada's Karyotypes. His staff said that they would look into it and get back to me on it.

What does having a copy of Vada's Karyotypes mean? Nothing, except I would be able to see the third, twenty-first chromosome! I don't need proof that Vada has Down syndrome, that's not why I asked for my own copies. I asked for them because the opportunity to see your own child's Karyotypes does not often come up. Most people will never have this chance, which is fine, but since I am in a situation where I can see them, I'm going to do so. Carpe diem!

After meeting with Dr H. we had to wait two hours before we met with Dr. Jennings, the Neurologist.

The visit with Dr. J. also went smoothly. No surprises, no real concerns. Everything is pretty much staying the same. We are continuing to wean Vada off of the ACTH and if everything goes well she should be off by mid November. We are changing her "maintenance" medication from Keppra to Topamax. She HATES the Keppra, it's incredibly hard to get her to keep it in her mouth let alone to swallow it. Were hoping that this new kind will be better for her to take. That in return would be better for me. It is so stressful knowing that these medications are her life line. If she doesn't take them the seizure will can come back and will take over. If I cant get here to take them, then it's my fault. Irrational or not, that's how I feel.

So the appointments were yesterday. Earlier this morning Dr. H's assistant called me to let me know on the progress of getting the copy of Vada's Karyotypes. She said something about them being archived and that it may take a couple of weeks to receive them. She also said that I needed to directly contact the hospital to sign release forms. No big deal.

The next thing she said was very unexpected. She asked if I was aware that Vada has Translocation Trisomy21. At first my heart started to race. At first I was confusing Translocation with Mosacisim . I knew what both were, I just got swept away for a second.

I was not aware that this was Vada's full diagnosis; Translocation Down syndrome. In all honesty, it doesn't mean anything different for Vada. Just an extra word to add on to one of her diagnosis.

For us, Justin and I, it could mean that every child we have from here on out would have Down syndrome. That would be, if one of us were in fact a "balanced parent". There is something like a 1 in 4 chance for that to be our situation, so for "piece of mind" she suggested that if we planned on having more children in the future, we should get genetic testing done.