Word Of The Day Is "Semilobar Holoprosencephaly"

Tonya and I got back from our appointment today with more information about our baby's condition.

Before I go further, a quick caveat: even though this is my unborn daughter I'm writing about, what follows likely will sound detached and clinical. I hope the tone and content doesn't offend anyone reading this; just consider it part of my way of coping.

And for many, what follows will sound like Too Much Information. If you are easily unsettled by descriptions of medical conditions, then the rest of this post is not for you. I'm writing this for friends and family who want to know the details about what's going on.

The news is not good; even if the baby survives for any length of time (which does not appear likely), she won't have anything that resembles a normal life.


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Our examination today was in the form of a very detailed ultrasound. Incidentally, the doctor said that Tonya--who, despite her added pregnancy weight, is naturally a slender person--has a body that is good for making high-quality ultrasound images of her inner bits. This also means that the things we saw today are almost certainly the real deal.

Here's a rundown of what was detected.


The Brain: our baby has what the doctor termed semilobar holoprosencephaly. The "holoprosencephaly" part basically means the brain has failed to split properly into left and right hemispheres. The "semilobar" part means that this is not a complete failure; some of the structures do exist in the right places. However, just because this is an intermediate form of holoprosencephaly does not mean it is a minor condition. In our little girl's case, there is some separation between hemispheres in the posterior portion of the brain, but the anterior portion is missing some important structures. In a normal brain, the brain tissue folds back and forth on itself in a big wrinkly mass; in our girl's, there is a thin, smooth layer of brain tissue lining the inside front of the skull, with a large fluid-filled empty spot just behind it where that big wrinkly mass should be.

And the cerebellum, which normally shows up on an ultrasound as two large side-by-side ovals right at the base of the skull, in our girl's case appear as a spindly mass on one side of the brain, unmatched on the other side.

The bottom line here is that our little girl is missing large portions of her brain. And, as is normal in such cases, her head is smaller than expected for her developmental age (microcephaly).


The Face: The development of the face is controlled by a lot of the same processes that control the development of the brain, and so when there is a problem with one, it is frequent for there to be a problem with the other. Our little girl is no different in this regard. In her case the ultrasound detected two abnormalities, both of which are common in cases of holoprosencephaly. First, the nose only has one nostril, centered; second, the eyes are spaced much more closely together than is normal. These two conditions together are called Cebocephaly.


The Heart: Several defects were detected in the heart--including its location, perfectly centered within the chest (as opposed to slightly on the left, where it should have been). It also appeared to be turned in an odd direction.

The most serious defect was referred to as a "trunc defect"; when I looked it up online, it appears the more technical term is Persistent Truncus Arteriosus. My understanding is this: the Truncus Arteriosus is a structure that is formed along with the embryonic heart very early in the pregnancy. As the pregnancy progresses, this structure is ultimately subdivided and split into the aorta and the pulmonary artery. In cases of Persistent Truncus Arteriosus, this subdivision never really occurs, and instead of a separate aorta and pulmonary artery, only a single blood vessel leads from the heart; both ventricles pump their blood into it. In fetal hearts this isn't necessarily a big deal, since their oxygen comes in through the umbilical (not the lungs) anyway; but after birth, when the lungs are supposed to supply the oxygen, this mixing of oxygenated blood from the lungs and depleted blood from the body results in insufficient oxygen getting to the rest of the body.

Also, a ventricular septal defect was detected as well; there's a hole in the wall between the left and right ventricles.


The Kidneys: Instead of two separate kidneys, our baby has one horseshoe-shaped kidney--or, rather, two kidneys that come around in front of the spine and join each other. Now, horseshoe kidneys don't always work. It appears, though, that our little girl's kidney is functioning; they were able to detect on the ultrasound two little, symetrical reservoirs of fluid that it had processed.


The Hands: The doctor was able to get a good look at one of the hands, and counted six fingers (or five plus a thumb). Also, it appears the thumb was folded over in front of the hand. We weren't able to get a good look at the other extremities, but strongly suspect that they are polydactyl as well. It turns out that polydactyly is fairly common as a "syndrome of congenital anomalies" (according to Wikipedia).


Those were the main findings, which they pointed out to us on the ultrasound.

Now, nearly all of these anomalies have something in common: they all (with the possible exception of the extra digits) are related to the development of left-right symmetry in the body. The holoprosencephaly is a problem that occurs when the brain fails to divide in half; the development of the close-set eyes and single nostril, involve facial features appearing too close to the centerline of the body; the failure of the Truncus Arteriosus to divide properly into Aorta and pulmonary artery; the failure of the heart to develop a strong wall between left and right ventricles; the failure of the kidneys to separate fully--all of these things suggested to the doctor a common origin. Any one of these symptoms can happen in isolation, as one-offs; but for them to happen all at the same time, suggests some kind of common cause.

The doctor thinks that there is a chromosome abnormality behind all of this. And, indeed, nearly all of the symptoms on the above list show up in the list of symptoms of Trisomy 13.


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If I have any readers who've forgotten their college biology, the cells of the human body each have 23 pairs of chromosomes, with one chromosome from each pair coming from the father, and one from the mother. These chromosomes contain all the "software" (actually, this is an excellent analogy) needed to build every protein the body needs. But every once in a while, as the cells are dividing, one copy will get a chromosome too many (or too few). The extra (or missing) genetic material can have unpredictable, and undesirable, consequences. If the cell that gets the extra (or missing) genetic material is a sex cell (sperm or egg), then every cell of the person formed when the sperm and egg fuse will have the wrong number of chromosomes.

If our little girl indeed has Trisomy 13, it means she has three copies of the chromosomes that make up pair number 13. Now, my understanding is that these chromosomes are heavily involved in building the structure of the body while in utero. This extra genetic material has thrown a proverbial monkey wrench into the entire process of fetal development, messing up one organ after another. As I mentioned above, any list of symptoms for Trisomy 13 contains many of the things we saw in that ultrasound today: polydactyly, holoprosencephaly, heart problems, face and eye problems, and other organ problems.

Of course, we won't know for certain that it really is Trisomy 13 until we get the results back from the amniocentesis. (And for all we know, it could still be Trisomy 18, which has a lot of similar symptoms, or some other condition.)


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So what is the prognosis?

Well....

With the exception of the problems in the brain, most everything else here is treatable to some degree or another. The doctor said that if the heart problems had happened in an otherwise normal child, the treatment and recovery--though difficult and dangerous--would be possible. And the kidney(s) seem(s) to be functioning.

But with all these issues at the same time--plus the fact that the problems in the brain can't be helped--her outlook is not good. The genetic counselor described for us the survival rate of Trisomy 13 babies, and it is pretty low. Most babies with the problems we're seeing never make it to full-term. Trisomy 13 babies that do, according to the counselor, have a median lifespan of two days. Only 5% make it to six months. And with what we learned today, we seriously doubt that ours would be in that number.


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So what to do?

Anyone who's made it this far into my little essay is probably wondering about whether we'd consider terminating the pregnancy. And truth be told, even though our attitudes toward abortion are what you would typically expect from conservative Christians, I don't think either of us would pass judgement on anyone in our position who decided to make that choice. However, that won't be us. The thought of taking her life--even when it's highly unlikely that she will ever become conscious--just does not sit well with us. We do not feel competent to decide when her life should end--that's God's job, not ours.

Our job, which God has assigned us, is to love her for as long as we have her.

So again: what to do?

The answer, really, is just to keep putting one foot in front of the other until we get where we're going. We know we'll lose her at some point in the not too distant future, but we don't know when and we don't know the circumstances under which it will happen.

If we do wind up going to full term--a probability that is not necessarily high--most likely they will schedule a C-Section. They don't want to do a natural delivery because that takes too long, and the baby's vital signs are hard to measure when the baby's internal organs are as nonstandard as her's are.

And then, we'll wait and see what happens.


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I've gotten a lot of comments from people over the last few days, telling me that they've been praying for us and giving us what encouragement they can. To all of you who've dropped in to support us with your thoughts, I want to thank you for your support. It really does mean a lot to us. I may not have the biggest readership on the planet, but I've got one of the best. Thanks!