Trisomy 13/Patau syndrome

Trisomy 13/Patau Syndrome Testing & Outcomes

If you’ve recently found out that your developing child has the chromosome abnormality known as Trisomy 13, you probably have many questions. I will try to answer all these and more:

What tests are there to detect Trisomy 13 and are they accurate?
How bad is Trisomy 13 in practical terms?
Can Trisomy 13 be cured?
What options do I have?
What is Trisomy 13 aka Patau Syndrome?
Should I abort this fetus?

Trisomy 13/Patau syndrome Infograph

You should always do your own research as this article was not written by medical professionals and is only a compilation of information put out by other medical professionals. I wrote this as a guide so you have a starting point and a good idea of the testing process, how to interpret the test results, and a workable understand of exactly what this disorder is and the impact it has.

Before I start – I just want to say, if your child has been diagnosed with Trisomy 13/Patau Syndrome, I am truly sorry. It is a horrible disease and it afflicts those who are innocent and defenseless, by definition.

Roughly speaking, the testing for trisomy 13 happens in three stages. Not all people do all three stages or any stages. Occasionally a parent will only find out about the disorder’s existence in the fetus when an ultrasound finds abnormalities, and in some rare cases an ultrasound will appear perfectly normal up until quite late in the pregnancy despite the existence of trisomy 13 in the fetus. Occasionally, most tragically, some couples find out upon birth. 90% of children with trisomy 13 do not live past their first year and all of them die young.

Now, what is trisomy 13?

There is no way to mince words here – Trisomy 13 is a very bad genetic disorder. It is not one of the less damaging genetic disorders such as Down syndrome, where the child with the disorder has a possibility of living a decent life. Trisomy 13 is objectively far worse; it always results in death, and it can occasionally even endanger the life of the mother. A diagnosis should be taken quite seriously and for the most part this diagnosis is functionally a miscarriage, but it’s extremely important you understand the testing processes to make sure that the fetus really does have Trisomy 13, and the basics of the disease so you can make informed choices as it relates to your health.

What are the stages of testing for Trisomy 13?

1st Test: In terms of testing stages, the first test is a DNA screening test called a NIPT (noninvasive prenatal testing), which becomes an option around week 9. It’s important to remember a screening test is not a diagnostic test. What that means is the screening test will give you a certain percentage of probability, but it will not give you a simple yes or no. It screens for Down syndrome, Trisomy 21 and other genetic conditions, Trisomy 18, known as Edwards syndrome and Trisomy 13 aka Patau syndrome.

The DNA screening test, although the same process worldwide, is referred to by different brand names in various countries. The most common brand name is called the Harmony test, and even if you’re in a country that doesn’t have that particular brand, if you say harmony test or DNA screening they should also know what you mean, but it’s best to say NIPT. 

Taking this test poses absolutely no risk to the mother or baby. It’s a simple blood sample, after which they check the blood for DNA fragments from the placenta, floating in your bloodstream, and use that information to determine how likely the fetus is to have trisomy 13. For Trisomy 13, the accuracy of the results is worse than for the other chromosome issues it checks for, such as Down syndrome, which can be as high as 99% accurate on the screening. Trisomy 13 screening only has about an 80% accuracy in predicting whether your child has trisomy 13.

Around 20% of mothers who get a positive result for Trisomy 13 on the DNA screening test will actually find out their baby is just fine. The wait for further confirmation tests is usually agonizing, but it’s a good opportunity to talk about what your plan of action will be with your partner, and explore all your options, since options get more limited as time goes on, and some have a brief window of possibility. 

2nd Test: The second stage of testing is the Chorionic Villus Sampling (often just referred to as a CVS test) which is available around week 10, but the results usually take at least a week to come back. Now this is an analysis of the placenta. This is a diagnostic test and it is the final diagnostic test for the placenta only. I’m making sure to emphasis that this test is only the final test for the placenta because it is rarely possible for the placenta to have Trisomy 13 and the fetus to not have Trisomy 13, if the chromosomal issue occurs somewhere down along the line of early development. The placenta, which is the area surrounding your fetus, is different from the fetus which is the developing child. And the CVS or Chorionic Villus Sampling tests is a diagnostic test only for the placenta.

If you take this test, there is around 1 in 50 to 1 in 350 chance of miscarriage, depending on the skill level of the doctor, what country you’re in, the type of equipment available in your hospital of choice, etc. So it varies from between a 0.33% chance to a 2% chance that this test will result in a miscarriage regardless of whether your child has Trisomy 13 or not. 

If your blood group is Rh (rhesus) negative, it will be recommended that you have an injection of anti-D immunoglobulin after the procedure to prevent you from developing antibodies against the baby’s blood cells. 

3rd Test: The third test is the amniocentesis, which is an analysis of a sample from the fetus itself and can be done from around week 15. This is a diagnostic test, and the final result for the fetus. So this is a sample from your developing child itself and it will tell you with 100% certainty whether your child has Trisomy 13 or not. There is around a 1 in 200 (2%) chance of miscarriage for this test. 

If your blood group is Rh (rhesus) negative, it will be recommended that you have an injection of anti-D immunoglobulin after the procedure to prevent you from developing antibodies against the baby’s blood cells. Results can take days to weeks and might come back in stages.

What are the costs for these tests?

Costs for these tests vary widely (make sure to get phone quotes from local hospitals and any relevant insurances, as well as getting quotes in writing via email as early and often as possible) but as a very rough overview of costs:

Australia: the NIPT screening (first test) is not covered by Medicare, so you will pay out-of-pocket for the screening, and it is usually around $500 AUD. However, as a test for an enormously wide range of different trisomies and genetic conditions it is worth every penny and I strongly suggest you get it. If you do have a positive result on NIPT for DNA screening, and you go to your GP and get referral, you might have certain options for a free CVS although it can be quite tricky. Occasionally a GP will tell you that you cannot get it under Medicare, generally that’s actually not true if you live in a major city. Usually you can, however it’s under a specific referral to a specific institution, and your GP will need to write the magic words down as a requirement first. Be firm and don’t be afraid to visit multiple GPs if you can’t afford the CVS by yourself. Medicare will refund a large part of the cost of an amniocentesis, but there are upfront costs. 

USA: the NIPT test is known as the Harmony test most commonly, and is usually $800-2000 USD without insurance, and significantly cheaper with insurance. Surprisingly, the Harmony test is usually much more expensive in the USA despite being a US product, even when exported to other countries and sold under the same brand name, so if you live close to a border medical tourism might be a cheaper option if you have no insurance. The CVS test can be around $1,300 to $4,800 without insurance, and insurance occasionally will not cover it. Amniocentesis can cost from $1,200 to $7,000 USD, without insurance. 

United Kingdom [UK]: The Harmony Test is widely available, the combined test is offered in England, Scotland and Wales for free on the NHS. However, if you live in Northern Ireland, you’ll need to pay to have it done privately., so is around £200-450. As for the amniocentesis being covered by the NHS, an ultrasound scan, the mother’s age and other factors such as smoking are combined to assess the likelihood of a baby having Downs. Anyone with a greater than one-in-150 chance of having a baby with Down’s, as measured by the GP based on guidelines, is offered an amniocentesis. If you are a non-citizen living in the UK, you can read about your medical rights here.

So what do the test results for the NIPT, Chorionic Villus Sampling, and Amniocentesis indicate?

Each stage has its own importance. The screening test tells you whether you need to worry about this condition at all. A positive result means you need to prepare for the likely outcome of your fetuses condition, this result means: more testing. The screening is a blood sample.

The CVS or Chorionic Villus Sampling is done with a needle into the lower abdomen and so is the Amniocentesis.

Now if you get a positive result on the placenta test you might be thinking why would I ever even get a fetus test, as the child definitely has Trisomy 13? This actually isn’t always the case. It is possible to have what’s called CPM, Confined Placental Mosaicism. Different parts of the fetus and placenta develop at different rates, and genetic abnormalities can be introduced either at conception, or later down the line during cell division, which means trisomy 13 can be confined only to the placenta without being present in the fetus. Your fetus can be perfectly healthy, but the placenta develops trisomy at a later stage in cell division, and the trisomy is held in the placenta and is only existing in the placenta and not your child. So if you have a positive result on the placenta test and there is no issue on the ultrasound, you might still have a healthy fetus, although it remains unlikely. The amniocentesis will be the confirmation in that situation. If you have a positive result in the placenta and there’s also a visible issue on ultrasound, it is nearly certain that the child does have trisomy 13, as the presence of a positive test in the placenta with the further evidence of physical deformities that early would be essentially conclusive.

However, if the ultrasound is perfect and only the placenta has been tested, some people will choose to get the amniocentesis later even if it means less potential termination options, in the hopes that maybe the child actually does not have trisomy 13, and it is actually the extremely rare Confined Placental Mosaicism which occurs in about one or two percent of cases. However, and this is a very important piece of information to consider, with CPM just because the fetus does not have trisomy 13, does not mean you are completely absolved of issues. 

Even if you do have the relieving result at the end of all that testing of CPM, unfortunately this could still lead to big issues for the mother and the child, because the placenta is essential to normal healthy growth for a child. The placenta having trisomy 13 can affect placental growth, placental expression and interfere with the essential functions of the placenta. Also mothers who have had a fetus with trisomy 13 Confined Placental Mosaicism have hyperthyroidism at rates well above 80%. So you are extremely likely to have blood pressure issues among a higher risk of many other issues as a result of having Confined Placental Mosaicism in your child. And the child, the fetus, itself can certainly be impacted despite being healthy as a result of the placenta being unhealthy and creating issues for the child, which could potentially be major. The implications of this requires sober and realistic consideration as to what options to pursue.

Since fetus Trisomy 13 is a death sentence, most people operate under the correct assumption that the child will die if there has been a diagnosis. And in light of that some people due to religious or other reasons will actually choose to keep the baby knowing it will die, because they do not want to have an “abortion” (which is really a miscarriage for all intents and purposes) for religious reasons or other interpersonal reasons. They would rather let the child die “naturally.” Unfortunately, a natural death is no longer an option, because there is nothing natural about dying from one of the most extreme genetic abnormalities. It is a heinously painful process, and can be quite long. There are at least two very important concepts to keep in mind when deciding whether to bring the Trisomy 13 affected fetus to term. 

One, is that the child will suffer before it dies, and many people would prefer to ease their babies suffering if the end result is unavoidable. I believe in general you should consider the child’s suffering and not your own. If there is no doubt about the diagnosis and only one merciful way out, most would take it. Conversely there’s also no guarantee that the child will die fast without an abortion and this might seem counterintuitive but this can actually be a bad thing because sometimes parents choose to keep the child, knowing the child is going to die, but the child becomes one of those extremely rare (<1%) outliers where the child lives to 7, 8, 9, 10 with extreme deformities and in extreme pain. 

Certain people who have not wanted to get abortions for moral or religious reasons not only have caused most of a decade of unimaginable suffering by a child but on the flip side they have also forced themselves to essentially go bankrupt and spend a decade of their life caring for and trying to ease the suffering of a child with Trisomy 13. So if you’re considering not aborting because the child will die anyway, keep in mind the child might not die straight away and the implications of that. 

Also keep in mind that as time goes on your abortion options become fewer and fewer and that’s also another factor to consider. So although the ideal situation, barring physical and financial limitations, is to wait for the amniocentesis, a rushed decision is often unavoidable. Even with CPM you will definitely have a higher chance of fetal developmental problems, fetus size problems, risk to the mother such as hypertension as high as 80% and also increased risk of preeclampsia or even still birth. CPM occurs in only one to two percent of CVS testing results. So it’s quite rare but it is possible.

Considering the extreme and painful nature of the condition, a quick and painless passing is, sadly, one of the best outcomes and that would be true even if it was not a fetus but a 50 year old adult – the abortion debate has very little, if not 0, relevance here. 

CPM occurs in one of two ways. The first is mitotic CPM, the second is trisomic rescue.

In layman’s terms mitotic CPM occurs as a result of the genetic error happening in a cell line in the tissue which is destined to turn into the placenta. So basically at some point there is an error at some stage, however as that cell replicates and grows and it just happens to be that it only grows into the part that is the placenta, it doesn’t affect the fetus. That’s mitotic CPM.

The other CPM is a result of trisomic rescue. What trisomic rescue is, is basically the fetus and the placenta might both have trisomy, however the body in an incredible process can actually quarantine and kill the cells that do have trisomy but they can only do it for the cells that have trisomy in the fetus. So it might be a situation where the fetus and placenta had complete trisomy but it was contained by the body into only the placenta.

By the way I would like to say in trisomic rescue the baby drops “drops” one of parents chromosomes and has two chromosomes from the other parent. So basically just to really understand what happening with trisomic rescue, which results in mitotic CPM, the baby will actually get rid of one of the parents chromosomes so that way they just have the normal two chromosomes but from a single parent. Now obviously we’re talking about normal and abnormal cells in the embryo.

There are three types of CPM. What I was explaining earlier was the two ways that CPM occurs; the two different pathways to CPM occurring. But once it occurs it might manifest in one of three different types of CPM.

Type 1 CPM; the error occurs in a trophoblast cell and thus only trophoblast cells are affected. This type of Mosaicism is most often associated with normal pregnancy outcome.

Type 2 CPM; the error occurs in a non-fatal cell of an inner cell mass. This trisomy is confined to the Chorionic Villus Stroma. This type of Mosaicism is described in normal pregnancies and is sometimes associated with a delayed growth of the fetus.

Type 3 CPM; trisomic cells are seen in trophoblast cells in the villa stroma but are absent in the embryo. This type of Mosaicism is more commonly associated with delayed growth in the fetus.

As you can see, knowing what type of CPM is present can help give you an idea of just what the actual odds are of a complication. Although of course there’s no such thing as a perfect science when it comes to predicting that. When predicting the likely effects of CPM several factors might play a role. The type of CPM you have can only be established towards the second half of the second trimester, so it’s quite a late stage situation, and by that point the knowledge might be useless as more certain results are there. So by the time you find that out options will be limited, however processes advance every day, and you should certainly ask your doctor about the possibility of knowing what type of CPM you have, although do not expect a solution until around the same time they can conduct the diagnostic amniocentesis anyway. The knowledge might answer other questions, however.

Trisomy 13 levels are not binary – it’s not a “has it” or “doesn’t have it” situation technically. For example, if the placenta has trisomy it might have 100% trisomy or it might have a 70% trisomy cells based on what portion of cells have the chromosome error. Same with the fetus, it could be 50% trisomy cells in the fetus or 90% etc. Somatic errors (errors appearing in the cells other than the sperm or egg) are far less likely than meiotic errors (errors appearing in the sperm or egg) to be associated with the ultrasound abnormalities, growth problems or detectable levels of trisomy in small samples of prenatal CVS. Errors of mitotic origin are correlated with higher levels of trisomy and placental tissues and may be associated with a first pregnancy outcome. The cell type in which that abnormality is seen is also an important factor in determining the risk of fetal involvement. The villa stroma or mesenchymal core is more likely than the sitotrophoblast to be reflective of the fetal genotype.

There is a correlation between a high number of any euploid cells detected at CVS (ex. 70%+ trisomy 13 cells) with poor pregnancy progress. This includes an association between high levels of abnormal cells in placental tissues and concerns with the growth of the baby. However, it is not accurate to use these associations that try to predict pregnancy outcome based on the percent of trisomic cells and a CVS result.
Most cases of trisomy 13 are not inherited and resolved from random events during the formation of egg and sperm from healthy parents. The small exception is if testing reveals translocation trisomy 13, you might have a greater risk of the same issue in the future.
Translocation trisomy 13 generally cant be directly and reliably inherited. A healthy person can carry a rearrangement of genetic material between chromosome 13 and another chromosome. These rearrangements are called balanced translocations because there is no extra material from chromosome 13. A person with a balanced translocation involving chromosome 13 has an increased but not certain chance of passing extra material from chromosome 13 to offspring, although an increase in risk doesn’t mean certainty. Your doctor can do various tests to determine if this particular, very rare issue lies within you. If you do have that particular issue, even then you can still try, although perhaps you should consider IVF if your budget allows as that would be a good option to prevent any additional issues, by allowing doctors to select the specific sperm and egg to introduce to each other.

If worse comes to worse, you may consider abortion to prevent unneeded suffering on the part of the fetus and yourself. There are a number of abortion options, although not all are available in every country or at every stage of pregnancy. Although it’s a tragic situation, you can at least take some small consolation from the fact that trisomy 13 is very rarely a result of genetics but almost always random. As you and your partner are clearly fertile by lieu of being pregnant, there is great hope to try and conceive again.

Abortion Options

Approximately 205 million pregnancies occur each year worldwide. Over a third are unintended and about a fifth end in induced abortion. In the United Kingdom for example, only 1 to 2% of abortions are done due to genetic problems in the fetus, and these are considered top priority for doctors, and as such you should always consult with as many medical professionals as you can about your options, and you should find them sympathetic and willing to help you. A pregnancy can be intentionally aborted in several ways. The manner selected often depends upon the gestational age of the embryo or fetus, which increases in size as the pregnancy progresses. Specific procedures may also be selected due to legality, regional availability, and the doctor’s or a woman’s personal preference – this article gives a good overview, and is a good place to start.

Many countries have specific help for those who have children or fetuses with genetic abnormalities, and these are often not necessarily listed publicly or advertised well if at all.

In the early stages of pregnancy, the most common abortion type is what’s referred to as a medical abortion, not to be confused with a medically necessary abortion. These are abortions done through the use of pharmaceuticals, usually by mifepristone in combination with a prostaglandin analog (misoprostol or gemeprost) up to 9 weeks gestational age, methotrexate in combination with a prostaglandin analog up to 7 weeks gestation, or a prostaglandin analog alone. Most of these options will not be available to you as it relates to Trisomy 13, as detection is almost always 10 weeks or later.

Up to 15 weeks’ gestation, suction-aspiration or vacuum aspiration are the most common surgical methods of induced abortion. From the 15th week of gestation other techniques must be used. There is Dilation and evacuation (D&E) which involves a doctor extracting the fetus manually, or a labour induction abortion. A labour induction abortion is when they simply induce labour, and the mother gives birth to the deceased child. This is very uncommon in the USA, but extremely common in most other first world countries, accounting for up to 80% of 2nd trimester abortions in Sweden. This is not as painful as normal labour, due to the smaller size, although it can be relatively traumatic. Some find this option superior because it has little to no risk for the mother or her fertility due to the natural process of elimination, and also many mothers find comfort in saying goodbye to their child in person, and seeing the baby and being able to hold it is of great comfort to them.

In the third trimester of pregnancy, induced abortion may be performed surgically by intact dilation and extraction or by hysterotomy. 

Hysterotomy abortion is a procedure similar to a caesarean section and is performed under general anesthesia. It requires a smaller incision than a caesarean section and is used during later stages of pregnancy.

First-trimester procedures can generally be performed using local anesthesia, while second-trimester methods may require deep sedation or general anesthesia. Induced labour is often done with morphine or an epidural to ease the pain and smooth out the experience.

You should never attempt a home abortion, whether through overseas pills or unusual methods. Without doctors to supervise and monitor the situation with legitimate pharmaceutical drugs, you risk enormous chances of injury or death to the mother, and it will be painful.

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