Down Syndrome and Alzheimer's

Although there are more immediate concerns I have for my little girl’s health, Alzheimer’s disease is something else she may face in the future. Studies have shown that genes on the 21st chromosome contribute to the aging process, and therefore an extra copy of 21 increases the risk of a degenerative memory disease.

I am choosing to write about this today because there was a recent conference in Chicago where experts in both Down syndrome and Alzheimer’s met to discuss the link between the two afflictions. In a study funded by Johnson & Johnson, individuals with Down syndrome will be the focus of research since the occurrence of Alzheimer’s is much higher in people with DS (roughly 25% show signs by age thirty, with the rate increasing to as high as 75% with age). 

In the past the life expectancy of an individual with Down syndrome was not much past 30, so the connection was not as evident. Now that individuals are living into their 60s, scientists see an opportunity to study a disease that slowly steals people from their loved ones.

The hope is that by monitoring those with a high risk from an early age (before symptoms manifest), they may able to do better understand the progression and to prevent the causes of Alzheimer’s (brain plaques and tangles). You can read the full article here.

One of the questions posed in the article is if parents of adults with Down syndrome would be willing to sign them up for these studies. I think about what I would do, and I suppose it really depends on what the study would entail. Would it be diagnostics and observations, or more risky drug trials? Would you sign up your son or daughter to be studied?

October is Down Syndrome Awareness Month!

In the past years, Down syndrome is becoming better understood as the community strengthens and strives to educate others. Unlike in the seventies where those diagnosed with DS were commonly institutionalized, there is now a realization that with the proper therapies and care people with Down syndrome can lead fulfilling, productive, and “normal” lives.

There is still a long way to go, however, when you consider that 9 out of 10 babies diagnosed prenatally with Down syndrome are aborted. I firmly believe that this statistic is largely due to a lack of understanding and knowledge. I discuss some of my personal thoughts on this matter in my post, A Choice.

They bottom line is though, despite all the possible health problems and developmental delays a child with Down syndrome may have, they will overcome more than you can ever imagine. They will amaze you every day and bring more joy and love than you ever thought possible. I believe this, and my baby girl still has 20 weeks left in my belly.

 

So, in honor of Down Syndrome Awareness Month check out your local Buddy Walk, an advocacy event to promote the inclusion and acceptance of people with Down syndrome.

Also, check out this "Wall of Awesome" at Noah's Dad.com, which is a post where parents can share their wonderful stories about raising children with Down syndrome.

What Causes Down Syndrome?

One of the foremost questions in my mind when I first found out my baby’s diagnosis was, “How did this happen? Was it something I did?"

I know my boyfriend was thinking similar thoughts, and blaming himself since he has a cousin with Down syndrome. In fact, when the doctor was initially telling us about all the screening tests offered, I wasn’t quite sure I wanted any performed. My boyfriend insisted, however, since my insurance covered the tests and he didn’t have much faith in his genetic line. This concern was despite the doctor’s opinion that his cousin was a distant enough relation that it was highly unlikely the Down syndrome would be inherited.

 

Three Types of Down Syndrome 

 

What I didn’t know at the time, and what wasn’t explained until after I learned the diagnosis, was that there are actually three types of Down syndrome, or Trisomy 21: Nondisjunction, which accounts for approximately 95% of all cases; Mosaicism, which accounts for 2-3% of cases; and Translocation, which accounts for the remaining cases and is the only inheritable type. My little girl, like the majority of those with Down syndrome, has Nondisjunction Trisomy 21. The genetic counselor briefly explained to me that this is due to the failure of chromosome 21 to separate which results in 3 copies in the affected individual.

 

It wasn’t until I got back home and fired up Google (or maybe it was Bing), that I started to truly understand how this occurred. I needed to have answers, because I couldn’t help but blame myself for causing my daughter’s Down syndrome. After all, I had done quite a bit of drinking between my sister’s bachelorette party and wedding before I realized I was pregnant. I had convinced myself that this is what caused my baby girl’s extra 21st chromosome. It may sound strange, but somehow it was easier to take the blame instead of just admitting that things beyond my control will just happen. What I learned made me realize that nothing I did caused the Down syndrome; it was then I began to truly accept the diagnosis.

  

Cause of Nondisjunction Trisomy 21

 

(This is the part of the post that seriously starts to nerd-out, so bear with me).

 

Rather than try to narrate the entire process which results in Down syndrome, I created a few diagrams based on my research. I tried to keep it as simple as possible, because most of us took biology a loooooong time ago (and probably don’t remember much about the following processes). Anyway, the following 3 diagrams depict how reproductive cells (sperm and ova) are formed. The first shows the normal division of the cells, and the next two show division of cells with nondisjunction (which causes Down syndrome).

 

You will see that the determination of Trisomy 21 occurs before fertilization. Researchers have yet been able to determine why this happens, although there is a link with maternal age. Oh, and just in case you forgot, a human should have 46 chromosomes total, 23 from each parent.

Here is how sperm/egg cells are normally produced (colored circles are the cells, and the number inside represents the total number of chromosomes):



It isn't really important for the purposes of this explanation, but notice that in the normal production of sperm cells, 4 gametes (sperm) are produced from the initial parent cell. This is in contrast to ova production, in which only 1 gamete (ovum) and 3 polar bodies (basically junk material) are produced from the parent cell.

These next two diagrams show the production of sperm/egg cells which will result in Down syndrome:



In the above representation, all of the resulting gametes are affected. However, only the ones with the extra chromosomes (24) are likely to produce a viable pregnancy. The child will be affected with Down syndrome.




In the above representation, half of the resulting gametes are affected. Again, only the ones with the extra chromosomes (24) are likely to produce a viable pregnancy and the child will be affected with Down syndrome.



Understand now?

A couple notes I would like to add.... Nondisjunction occurs 85-90% of the time during oogenesis, which means that the majority of Trisomy 21 cases are due to an extra chromosome from the mother. Also, I mentioned below the pictures that the lack of a chromosome would not likely produce a sustainable pregnancy. This is true in regard to the 21st chromosome. However, a pregnancy can be carried full term if the nondisjunction occurs to the 18th chromosome and the gamete with the missing chromosome is fertilized. This is called Turner's syndrome.

So what about the other types of Down syndrome?

Mosaicism occurs after fertilization when the cells begin to divide and multiply. Some of the cell divide normally, and some of them don’t. This results in an individual having some cells with the normal 46 chromosomes, and some with an extra copy of the 21st chromosome.

Translocation, as I mentioned earlier, was the only inheritable type of Down syndrome (although it can occur sporadically as well). When it is inherited, a parent carries a translocated chromosome; in the case of Down syndrome this means one of the chromosomes from the 21st pair is attached to another chromosome, usually the 14th. Even though the chromosome is in the wrong spot, the parent still has the correct number of chromosomes and therefore does not have Down syndrome. However, during meiosis this translocated 21st chromosome is copied along with the 14th into the gamete, which results in Down syndrome. The individual will have a normal pair of the 21st chromosome, and third copy attached to chromosome 14.

I also will point out that all types of Down syndrome affect an individual the same way, and only a genetic test can positively identify which type an individual has.

Phew…. I hope all that makes sense! I apologize for the technical nature of this post, but I wanted to share with those that were curious how Down syndrome actually occurs. Also, if you know someone with Down syndrome or who is about to become a parent of a child with Down syndrome, you will now have some knowledge of the causes.

My Mission Statement

Although I have already written a couple posts, I would like to introduce this blog in a more proper manner. The subtitle pretty much says it all; I will be writing about my pregnancy and eventually about raising a child with Down syndrome. If you have read my first two entries you know they were very personal and ventured into some deep emotions. Not every post will be that way…I want to be able to capture all aspects of this journey. In the future expect ramblings that reflect elation and joy, fear and apprehension, silliness and lightheartedness. Above all each one will be honest about my experiences in hopes to inspire, educate, or just entertain. Thank you for taking the time to visit my page; I hope you will return and follow me on my adventure into parenthood!

Much Love,

Meghan

A song I feel is quite appropriate :)

A Choice?

I will start this post off by offering one more statistic:


Over 90% of babies diagnosed prenatally with Down syndrome are terminated

Abortion?

I don’t know about you, but my stomach literally turned when I read that fact. It just didn’t seem like it could be real…but sadly it is. I am not here to argue the basic premise of pro-life or pro-choice, because I do believe there are situations where woman should be given full control over their own bodies. What does bother me is that 90% had already made the choice to continue the pregnancy.

I make this assumption because a CVS to confirm diagnosis of Down syndrome is performed around 11-13 weeks, or an amniocentesis is performed around 15-18 weeks. If those women didn’t want the baby I doubt they would even be that far along in the pregnancy, or for that matter even be undergoing the tests in the first place.

So why if they had previously chosen life, do they suddenly decide that life wasn’t worth a chance anymore? Of course I can’t answer this question myself, but I do have a theory. Their image of the perfect family, perfect children, and perfect world has been invaded. Thoughts of anguish and sorrow have surrounded them. Preconceptions of what a child with Down syndrome will be ambush their conscience and reason, and they forget that first and foremost she will still be just a child…their child.

Of course, I am not going to pretend it is the easiest path to walk down. There will be unique hardships to face, but there will also be unique joys to experience...ones that will make the hours spent in physical and occupational therapy worth every minute. In fact, these therapies sessions can be a fun and wonderful bonding experience with your child, and the pride felt when she reaches a goal will be indescribable. Or so I’ve been told (read... check out Noah's Dad).

Perfection?

The thing I ask then is, what guarantee did these women ever have to believe their child would be perfect? If a doctor could tell them in advance that their child will have colic, severe allergies, juvenille diabetes, a lisp, a birthmark covering a large portion of the face/body, or be anything other than society’s view of "perfect", would they terminate the pregnancy? This may seem like a silly analogy, but isn’t that pretty much what they are doing? The doctor says Down syndrome, but what they hear she will never be be "perfect". I think they are afraid she will look different and never go to prom, go to college, get married, or be view society’s view of successful.

Therein lays the problem. Who says she will never do these things? These are imaginary limits placed on the Down syndrome community that are only bolstered by society’s perpetuation of them. I may be new to this world, but I am determined that my daughter will not be held back because people tell her she can’t do something. I realize that some of those things may not be the norm, but nothing is impossible. In the words of Ralph Waldo Emerson,

“To laugh often and much;

To win the respect of intelligent people

and the affection of children;

To earn the appreciation of honest critics

and endure the betrayal of false friends;

To appreciate beauty, to find the best in others;

To leave the world a bit better, whether by a healthy child,

a garden patch or a redeemed social condition;

To know even one life has breathed easier because you have lived.

This is to have succeeded.”

[I do want to point out that I am ignoring some specific health concerns of babies with Down syndrome; for example, approximately 50% of babies will have some type of heart defect. However, according to my research and discussions with the doctor these conditions are either treatable by surgery, will just need to be monitored, or will resolve on their own. Again I ask though, what guarantee did these mothers have that any other child wouldn’t face some type of health issue? Also, there may be an argument of additional financial burden. However, I have found through my research that most states have sponsored early-intervention programs. In addition there are supplementary insurance options which are not always income based, or based on income levels well above what typical welfare-type programs are based on].

The Beginning

I would like to kick off this blog by throwing out a few random odds, taken from Funny2.Com: 

1 in 280,000 = Being struck by lightening
1 in 11,500 = Bowling a 300 game (not Wii bowling, of course)
1 in 5,000 = Getting a hole in one
1 in 19,556 = Incurring injury from fireworks

 Interestingly enough, I or someone close to me have known someone personally who have been that “1” above……clearly defying all odds. So here is one more statistic taken from another website, which is the inspiration for the title of this blog: 

1 in 1000 = A mother of 30 conceiving a child with Down syndrome

In retrospect it doesn’t seem so impossible that I am that “1” this time.

The fact is though that barely a week ago I never once thought that my baby would be born with an extra chromosome. I had been greatly anticipating my 12 week appointment, at which was scheduled an NT scan. I was excited at a chance of being able to actually see my little one on the sonogram and hear the heartbeat, as opposed to just a little blob which the technician told me was a baby. And that is exactly how the appointment started….

I saw my little baby dancing around on the screen, waving, sucking her little thumb. I heard her heart beating at a strong 168 beats per minutes. Lying back with an amazing feeling of love, the technician started into the the true purpose of why I was there. Of course I had no worries. She wiggled the wand across my belly and was clicking away on the screen. I watched her move a cursor, measuring the fluid behind the baby’s neck. I watched her face briefly show a moment of concern. She wiggled, clicked, measured again. Then the words came, and I immediately knew that something wasn’t right. She excused herself from the room and told me she was going to get the doctor.

From that point forward, everything was surreal. The doctor also wiggled, clicked and measured….. He calmly explained to me what they were seeing. The fluid behind the baby’s neck was measuring at 3.7mm. According to the doctor, at my baby’s gestational age the maximum they would prefer to see is 3.00mm. Ideally, however, it would be much less. The amount of fluid immediately raised the risk of a chromosomal disorder to high.

The doctor also was detecting a hygroma, a fluid-filled cyst, on the back of the baby’s head. He told me approximately 60% of the time these are caused by a chromosomal abnormality. Between these two things he saw on the sonogram, the doctor was quite certain my baby had a genetic syndrome. He offered a test that could tell me with over 99% accuracy. I did not hesitate to say yes. I will not go into the details of the what the CVS involved, but I will say it was a terrifying. Especially because I was alone, and probably more so because deep down I already knew what the results would be.

Two days later, I received a phone call from the genetic counselor. She confirmed my baby has Down syndrome. I let go of the small sliver of hope I was holding onto, and so begins this journey. It is one I am not quite sure I am prepared for, but one I am willing to embark on.