The B Life: About Trisomy 13 & Joseph

About Trisomy 13 & Joseph


Trisomy 13 is a genetic anomaly where a person has three copies of Chromosome 13. Most of us have only two copies of each chromosome, thus making us pretty usual. There are three types of trisomy disorders: Down Syndrome (Trisomy 21), Edwards' Syndrome (Trisomy 18) and Patau Syndrome (Trisomy 13). The latter two are generally more physically and neurologically serious - and more rare - occurring in only 1 out of 15 000 live births. 

The medical community has generally regarded both Trisomy 13 & Trisomy 18 as "Incompatible with Life." This is because, statistically, only 10% of children born with a full trisomy 13 or 18 will live past their first birthday because the physical abnormalities are often life threatening even beyond modern medicine. Although, the statistics ARE changing as the medical communities are becoming more aware of what T13 kiddos are able to handle medically and physically. 


There are a few types of Trisomy 13. Most are NOT inherited. 

Full Trisomy 13
This simply means that a person has 3 copies of the 13th chromosome in every cell of their body. This is the most common form of Trisomy 13, and also tends to be the most serious. Children with a form of Full Trisomy 13 often have more serious physical and neurological impairments.

One form of Full Trisomy 13, is when it occurs in a translocation. This means that the 13th chromosome has replicated itself and attached to another single-arm chromosome (often 8, 14, 15, or 21). This is the type of Trisomy 13 which Joseph has. It is also the ONLY type of Trisomy 13 which can be inherited from a parent (more on that later). It occurs in only 20% of full T13 cases. Of that, it is approximated that only 50% or less of those cases are actually inherited.

Partial Trisomy 13
This means that a person has a partial replication of the 13th chromosome in all or part of their cells. Often, this version of Trisomy 13 is less serious as the medical complications and impairments which come with this type are lesser and more manageable.

Mosaic Trisomy 13
This means that, although a person has a fully replicated 13th chromosome, it is not consistent in every cell. With this type of Trisomy 13, a person can have all or none of the features of Trisomy 13. They can also fall somewhere in the middle. There is no baseline here as each individual is so unique and no two genetic make-ups are exactly the same.

As I continue to blog, you'll find out about how I discovered that I have something called a Robertsonian Translocation. In layman's terms, that means that I have all my chromosomes, but they are rearranged. I have one chromosome 13 attached to a chromosome 14. While all my genetic information is there, it looks a little different than a normal genetic arrangement. This means that when Joseph was conceived, he received a chromosome 13 and a chromosome 13/14 combo from me (green chromosomes pictured below). 
Here's where things get confusing (or maybe hopeful) for us. While Joseph is full Trisomy 13, no one is sure if his translocation changes the severity of his version of T13. We do know his development will plateau at some point. But we've been blessed that his medical issues have been EXTREMELY treatable, and other than some extra digits (which were removed), he has no outward physical abnormalities that would prevent him from learning how to do life at his own speed.

We're also challenged by the fact that Joseph was born 7 weeks early. The conversation for the first year of his life will always teeter between whether developmental delays are due to his early arrival or his Trisomy diagnosis.

Medically, Joseph suffers from:
1) Tracheomalacia; basically a floppy airway which collapses once in a while. Because of this, he suffers from sleep apnea. He sleeps with a biPAP machine, nightly, to insure restful sleep and full breaths.
2) Nocturnal seizure activity. Basically, Joseph will have seizures if he startles awake. These can vary in severity, but don't typically last longer than 90 seconds. He breathes through them, and receives Keppra 2x daily to minimize the seizures.
3) Hypertonic muscle tone. Joseph has stiff muscles which is neurology suspects is tied to his nervous system. We also expect that along with the stiffness, he has low muscle tone - which may make milestones such as standing, crawling, or holding himself up delayed.
4) He has rocker-bottom feet.
5) He has a large Coloboma in his right eye. We expect this has impaired his vision, but not fully.

However, at 6 months of age (4 months corrected), Joseph is able to do the following:

- Smile socially
- Roll from his side to his back, and to his side again
- Swat toys
- Hold his head on his own
- Gurgle and coo
- Suck his fist (since he's hypertonic, the thumb sucking still eludes him)
- Eat by bottle during the day (he has a g-tube for overnight feeds)
- Reach for/swat at his fur siblings
- Follow voices and light with his eyes


Since most of these milestones are pretty "normal" for most 4 month olds - and that *is* his corrected age, we just take every day as it comes. 

While genetics are confusing, it's also pretty cool. We're astounded, every day, that WE have been given the gift of Joseph - we've been entrusted to care for him - and since I have the gene that caused his abnormality, we are able to recognize that he was ordained all along. 


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