I’ve been thinking a lot about genetics lately. It’s fascinating to me, although I’ve not been able to delve very deeply into the topic. My biology teacher in college loved genetics, but was only able to spend a short time on the subject — yet she was obviously passionate about it.

Sometimes knowledge isn’t all it’s cracked up to be, though. One of the genetic diseases I remembered learning about was cri du chat (which is French for “cat’s cry”, because the children born with this problem — a deletion of information on the 5th chromosome — sound like a cat meowing when they cry). I was also studying French at the time, and it was just one of the things I always remembered. So, several years after that, a woman in our church had a baby, and everything seemed to be going fine… but about six weeks after the baby’s birth, my mom mentioned that the baby had “a funny cry — when he cries he almost sounds like a cat meowing!” Of course I remembered what I had learned in college, and told my mom; then looked up more information on the internet (at 26.6kbps download! — remember those bad old days of dial-up??), and confirmed what I had instantly suspected. As page after page after page said the same things, and I had a little mental check-list of how this baby fit this or that symptom, I felt horrible — almost as if I were giving him the disease, rather than just recognizing it. And then to tell his parents…! Yet that’s what genetic counselors and doctors do every day — tell loving parents that their child has some problem.

My late pastor’s youngest daughter also had a genetic problem — Trisomy 18, which used to be considered 100% fatal, but now it is known that it is not always fatal. One interesting thing about her, though, is that not all of her cells are affected — some of her cells are normal. It’s called mosaicism — like a mosaic made up of all different tiles, some cells are of one type of “tile” while other cells are another type. I’m guessing that what happened is that early in her embryonic development — say, back when she was just 3-4 cells — one or more of her cells lost the extra chromosome and continued their normal development, while the others kept the third 18th chromosome and continued their abnormal development (or perhaps vice versa — I don’t know if it’s possible for normal cells to mutate or divide in such a way that they can develop and pass on a third chromosome, or if it’s only possible for a 3-to-2 division). People with genetic conditions like this who are mosaic tend to have milder symptoms of the problem than those that are affected in every cell.

But other times, genetics can be very cool, because even when it appears that some people are vastly different from each other, we’re really all about the same inside. Like this story demonstrates (below is the picture from the story).

One of these men was a good match for a kidney donation to the other man

One of these men was a good match for a kidney donation to the other man

We might think that these two men had nothing in common, but we’d be wrong. There was so little difference between them, that one man was able to donate a kidney to the other man. Close relatives of the man who needed a kidney were not a good match; but his good friend was. How cool is that!


Ok, Sailorman!

Several weeks ago, somebody on Dr. Amy’s blog derogatorily linked to my Ask Dr. Amy post, so I checked out the thread and left a comment. Naturally, in her short comment about it, Dr. Amy managed to lie about me (said I constantly [or was it “frequently”?] complain about not being able to understand her — I guess she forgot that she is the one who said, “I’m not really sure what you’re arguing about” (first comment); while I say that I do understand what she’s saying — I just happen to disagree with it), and then misrepresented what I had said on a previous thread (implied that I couldn’t make it on my blog without her linking to me so her readers could click from her blog to mine). At the time, I doubt that I’d gotten so much as 100 hits from links she’s done in the past; although in the flurry of the next few days, I got about 200 hits just from that one thread. And not one comment on my blog in answer to any of those questions, which was disappointing.

A few weeks later, I looked back on the thread to see if there were any responses, and there was one from Sailorman (I’m assuming female, despite ‘man’ — maybe it’s her last name? not really sure — of course since most people interested in birth are female, odds are this person is female, so I will use the feminine pronouns — if I’m wrong feel free to correct me), in which she said she’d respond to them on her blog. I clicked over to the post, saved the contents of it, and was ruminating on what to say. Obviously, with nearly 40 questions (some multi-part) on my original post, if I had tried to respond to everything she said, it would make for a very lengthy comment, so I was ruminating about what to say. I began a comment but it ended up being so long (I have a difficult time not trying to hit every point, even when aiming for a short comment or post), that I abandoned it and thought more of what to do. “Life” also intervened (sick kids, mother-in-law visit, husband busy at work, etc.), so it was easy to put it off “one more day” several days in a row.

Finally, I decided that I would see if she really wanted to discuss things, or if she was going to “go Dr. Amy” on me and shut me down, call me ignorant, refuse to listen to my side of the argument, etc. So, I was going to post a comment about one point she made (in response to question #17, in which I said something about “many people say” that 95% of babies with conditions such as Down Syndrome and anencephaly are aborted) — she said it was easy to say that and requested that I back it up. I figured that if I posted the links in a comment, it would automatically be filtered to spam (since comments that are heavy on links are so many times just spam), so I was going to post the links in the comments section of the Ask Dr. Amy post, and post a comment on her blog letting her know she could look at them there. However, I realize that I have them under my bookmarks on delicious (katsyfga), so you can just go to delicious, click on the menu bar named “people”, put in my username, and you will be taken to my bookmarks. From there, you can click on the tag “abortion” (it has 27 different items, but only about 6-8 actually deal with termination rates of fetuses with Down Syndrome or other conditions) and see what they are.

This morning, I tried to find her blog, and discovered that her blog is invitation only again (she had changed it so that I and others could go to it and see the post and ensuing comments). I’m going to post the links here, and I’m using her name in the title, in case she happens to see it.

Dr. Amy — if you’re still reading my blog, you can let her know that I have done this, and if she’s interested in a fair and open discussion, she can leave a comment here or anywhere on my blog so that we can communicate. I don’t mind having this on my blog, hers, or by email, but would prefer email because I imagine the comments will get fairly long, and it can be difficult to type so much in a tiny box, and there may be limits placed on the lengths of comments, or the number of links allowed. You can also let her know that many of her comments and questions were already answered at length in posts I had previously written on my blog, which I linked to in that particular post. If she’s interested in understanding, for example, more about why I asked you about the intrapartum mortality rate, or my discussion on low-risk and high-risk midwife attended birth, or certain other questions about the various things, she can read the posts I wrote months ago, and if she still has questions or wants to discuss this, she can open her blog to me or direct me someplace where we can discuss this. Much of this particular paragraph is what I was intending to say on her blog, but cannot do it now because it’s a closed blog, and I don’t have her email address to be able to get in touch with her that way.

Anyway, I’m disappointed that I can’t discuss this with her. I’m not sure if it would be a fruitful discussion, but I had hopes that I could at least have an intelligent conversation with her. Maybe I’ll get the chance in the future.

I’m flabbergasted!

A doctor who was recruited from Germany to fill a position in Australia that was underserved has been declined permanent residency because his son has Down’s Syndrome! The reasoning stated is that the government is concerned that the boy may have expensive medical needs which the Australian socialized medicine system (i.e., the taxpayer) will have to pay for. What next? Forced abortions on women who discover that their babies have Down Syndrome or some other problem to save money?

Down Syndrome, Prenatal Screening, and Amniocentesis

I recently came across this article which said that there are “160 healthy babies lost for every 50 Down’s cases detected with amniocentesis.” That’s an exaggeration which reminds me of the recent post I wrote about Skewing the Statistics. Here are the facts: amniocentesis is recognized as having a 1 in 200-400 risk of miscarriage; and the risk of having a baby with a genetic condition such as Down Syndrome is about 1 in 1000. So, if every pregnant woman were given an amniocentesis to accurately assess whether the baby had Down’s, then (estimating 4 million births per year) about 10,000-20,000 babies would be miscarried as a result (most of them healthy), while only about 4,000 babies would actually have Down Syndrome or other similar genetic condition. But not every pregnant woman is given an amnio. Typically, women are offered an amnio if they are at risk of having a baby with a condition that an amnio can predict — for instance, if they are over a certain age, or if a screen such as the nuchal translucency test indicates that they are at high risk for having a baby with Down Syndrome or some other condition. However, if doctors are being encouraged to offer women amniocentesis as a matter of course, then, yes, that article would be correct, and an extraordinarily high number of babies will be miscarried that otherwise would be carried to term.

There are various screening tests that can be performed prenatally, but their accuracy varies, depending on the type of the screen and what is being screened for. In looking at screens such as the nuchal translucency test, they typically miss about 15-25% of babies who have Down Syndrome, and inaccurately flag about 5% of babies as being “high risk” for Downs when they’re not. So, if all (4 million) pregnant women got the NT test, and 85% of DS cases were accurately identified (3400), and 5% of women are inaccurately identified as high-risk (200,000), and all “positive” results were further tested by amniocentesis with a 1:300 risk of miscarriage, then 11 babies with Down Syndrome will be miscarried, and about 667 babies without Down Syndrome will be miscarried. So 600 babies with Down Syndrome would be missed, 3400 would be discovered, and 667 normal babies would die by miscarriage. However, these results will be different, depending on the real-life risk of miscarriage from amniocentesis (it varies, based on the provider’s skill and how many he’s done, as well as when in pregnancy it’s done), as well as on the accuracy of the NT test. If, as the author of the above-mentioned article says, the NT screening is not as accurate in the real world as it seemed to be in the research environment, and there is an even higher false-positive rate, then more babies will be miscarried due to invasive tests such as amniocentesis which would not have been done had their mothers received an accurate negative result.

This study was interesting, in that it talked about tests other than nuchal translucency, to determine women at higher risk for having a baby with Down Syndrome (or other condition). (Here is the table provided in the study which shows 7 different ultrasound markers used to identify babies at higher risk of having Down Syndrome.) If all babies found to have “choroid plexus cyst” were subsequently given an amniocentesis to test for Down Syndrome, then there would be so many miscarriages due to amniocentesis, that for every ten babies positively identified to have Down Syndrome, another forty-three normal babies would die. As maternal age increases, so does the likelihood of having a baby with Down Syndrome; if only women at high risk are screened, then the rate of fetal losses drops to just under two dead normal babies for every baby found to have Downs. (Let me say that this study does not look at nuchal translucency, which has recently been recommended to be offered to every woman, although not every doctor has the expertise to perform it. This study is for second-trimester ultrasound screening, and the nuchal translucency is a first-trimester test.)

Having a “false positive” rate of 5% sounds pretty good, until it appears that if 5% of the population is wrongly identified as being at high risk for having a certain condition, then that equals 200,000 women and babies. That’s a lot!

I encourage you to read the study I linked to, especially the comment section, because it has a lot more information, but here is one quote:

The use of the ultrasonographic markers as an indicator for invasive testing with amniocentesis will lead to an increase in the number of unaffected fetuses lost as a complication of the procedure…. this highlights an important potential harm associated with a test often considered risk-free. If, for example, identification of an echogenic intracardiac focus is used as a basis for offering amniocentesis to pregnant women at low risk of carrying an affected fetus, 2 unaffected fetuses will be lost as a complication of amniocentesis for each correctly identified Down syndrome case. Additionally, because the false-positive rate is 1% or greater for most of the markers, when all of these markers are used in aggregate, the false-positive rate may approach 10% or more, leading to much needless anxiety throughout pregnancy and beyond.

In a previous poll, I asked how many babies with Down Syndrome were aborted, when their condition was discovered in utero. The answer is 85% or more. Most studies show at least 90-95% termination rates, but I won’t link to all of them.

Down Syndrome

Does anybody remember the TV show “Life Goes On“? It was a show about a normal family who had a son with Down Syndrome, played by Chris Burke. I’ve been thinking more about Down Syndrome ever since Sarah Palin was announced as McCain’s running mate, and it was said that her youngest child has Down Syndrome. So it’s been in the media more.


(The correct answer is included in this post. Check it after you vote.)