If you have just received a prenatal diagnosis of Trisomy 13, I'm sure many questions are going through your mind. What is the cause of Trisomy 13 (Patau's syndrome)? What does this mean for my baby? Is there any treatment? What would it be like carrying to term? What will my baby look like? Where can I find stories and pictures of babies with Trisomy 13? Where can I find support from other parents who are raising a child with Patau's Syndrome?
We had the same questions when our daughter Abigail was diagnosed with Trisomy 18. Many of the emotions, experiences, and decisions are very similar to your experience with Trisomy 13. You can see how we found the answers to these questions in Abigail's Story and Pictures and we would like to share with you what we have learned.
What is Trisomy 13? What causes it? Trisomy 13 occurs when a baby has three chromosomes in the thirteenth position instead of the normal two. It is also called Patau's syndrome, and is the third most common trisomy, after Trisomy 21 (Down syndrome) and Trisomy 18 (Edwards Syndrome).
Most trisomies are full trisomies. That is, the extra chromosome occurs in every cell in the baby's body. This type of trisomy is not hereditary, and it is by far the most common type. In most literature, and on this website, Trisomy 13 or 18 means full Trisomy. These three trisomies: 13, 18, and 21, are the only full trisomies which have ever led to a live birth.
There are also partial and mosaic trisomies. Mosaic trisomies occur when the extra chromosome is present in some (not all) of the cells, and partial trisomies occur when only part of an extra chromosome is present. Some partial trisomies are translocations, usually caused by a parent's translocation, which may be hereditary. For more information, see Translocations from the Genetics and Public Policy Center.
Like Edwards syndrome, Patau's Syndrome is usually fatal, with most of the babies dying before birth and those who do make it to birth typically living only a few days. However, a small number of babies (<10%) live at least one year (ref 1,2). For more information about how trisomies occur and the odds of having a baby with a trisomy see Aneuploidy from the Genetics and Public Policy Center.
After much learning ourselves, we explained Trisomy 18 very simply to others in A Letter to Our Friends that we gave them at our daughter's memorial service. A similar method may be helpful in explaining Trisomy 13 as well.
How is Trisomy 13 diagnosed? Sometimes a mother's AFP or quad screen test comes back as high risk for Trisomy 13 (ref 3). It is important to note that this is not a diagnosis, but a risk. When an AFP test indicates a high risk for Trisomy 13, usually a Level 2 ultrasound (also called a targeted ultrasound) is scheduled. The level 2 ultrasound is usually performed by a perinatologist or someone else who specializes in high-risk pregnancies. They are specially trained to look for the markers of Trisomy 13. These markers, often called soft markers, are characteristics frequently seen on babies with Patau's Syndrome.
And even if multiple markers are found in an ultrasound, this is still not a diagnosis of Patau's Syndrome. The only ways to know with nearly 100% certainty that your unborn baby has Trisomy 13 is to do an amniocentesis or CVS (chorionic villi sampling).
The amnio results typically take 10 days or more, but there is a FISH test that can give preliminary results in a few days. From the amnio, they do a karyotype of your baby's cells, which will clearly show the extra thirteenth chromosome if it is present, indicating Patau's syndrome (see a karyotype of Edward's Syndrome [trisomy 18]). For a good description of all of these and other prenatal testing options see Prenatal Genetic Testing from the Genetics and Public Policy Center.
At this time, if you have a definite diagnosis of Patau's Syndrome, you are typically presented with the option to terminate the pregnancy. However, that is not the only option you have. The first thing to do is slow down and learn about Trisomy 13 and all the options before you make a decision that you will have to live with for the rest of your life. We chose to carry our daughter to term, and you can read about all the options you have, the benefits of carrying to term, as well as some of the MYTHS of Trisomy 18 (most of which apply to Trisomy 13 as well) in the Carrying to Term Resources section of this site.
What symptoms will my baby with Patau's Syndrome have? How long will my baby live? There are many and varied symptoms of Trisomy 13. In addition to the ones identified via ultrasound, babies with Trisomy 13 often have microphthalmia (small eyes) and coloboma (an iris tissue defect), low-set ears, and a small head. Many also have holoprosencephaly (failure of the forebrain to divide properly), which can affect facial development, leading to close-set eyes or underdeveloped nose. The majority of babies with Trisomy 13 also have cleft lip and palate and congenital heart defects.
There are several sites which list the symptoms of Patau's Syndrome from a medical standpoint: Medline Plus Trisomy 13 is one, Lucille Packard Children's Hospital Medical Genetics Trisomy 18 & 13 is another, as well as Pediatric Health Encyclopedia Trisomy 13. In addition, Trisomy 13 Facts from SOFT, is written by Dr. John Carey, probably the premier expert on Trisomy 13 and 18 in the world. However, your baby is much more than a list of symptoms. The best way to get a feel for what it will really be like to have a baby with Trisomy 13 is to meet other families who have been through it.
It is very difficult to predict exactly what problems your baby will have because of Trisomy 13. Even though problems may be identified during ultrasound, there is really no way to know how long your baby's life will be. Many babies with very severe heart defects make it to live birth and live for weeks while many with few obvious abnormalities on ultrasound die in the womb. Your doctor does not know which group your baby will fall into by looking at an ultrasound. And after birth, it is also hard to tell which ones will live longer.
Where can I find stories of babies with Patau's Syndrome? Reading about others' experiences will help you better understand more of the possibilities for your child. You can find links to stories of babies with Patau's Syndrome on Abigail's Friends page of this site. The whole gamut of experiences is expressed and will help you see the possibilities for your child. There are many stories and photos of other families whose children have trisomy 13 at Living with Trisomy 13.org. You can also meet other parents of children with Trisomy 13 on the Trisomy 13 Support Bulletin Board.
There are several sites with very good information and support about Patau's Syndrome:
Although this is a very difficult situation, there is a lot of support available - you are not alone. I have also included a section of Grief Resources to help you grieve your child. There is also a section for friends called Helping a Grieving Friend. This is a strange journey; in many ways the grieving starts at the diagnosis, even before we lose our children. I hope that this site can be of help to you as you travel this difficult path.