Genetic Testing Results

This post is really for those of you affected by rhabdoid tumors that find this blog.  The rest of you might not be interested in the medical part of it- and that's fine!  I'm going to try to explain the results as I understood them (and hopefully the genetics class that I am taking this semester will help me more in the future!)

Rhabdoid tumors (like most tumors) are genetically related.  That means that within most tumors, the cell make up is different than those of normal cells.  The difference between tumor cells and normal cells- or in this case rhabdoid cells and brain cells is that the rhabdoid tumor cells keep reproducing and don't stop.  Almost all cells reproduce- which is good usually.  Kind of like when you cut your self, and the cells around the cut reproduce in order to clot and then heal the area.  But those cells stop reproducing when the infected area is healed.  Tumor cells, as a general rule, keep reproducing until they 1) run out of space or 2) are killed.

So onto the genetics part.  Rhabdoid tumor cells are missing a tumor suppressor gene within the cell make up.  (Specifically it's the chromosome 22 hSNF5/INI1 gene that is deleted.  Not important unless you are into this kind of thing!) SO basically ONE gene on ONE chromosome of ONE cell causes this tumor. 

The question for the genetic testing boiled down to whether James was missing the tumor suppressor (INI1) in every single cell in his body, or whether the tumor suppressor was only missing in the tumor cells.  And if the INI1 deletion was detected in every cell (which they test in his blood and spinal fluid), then was it because he inherited this deletion from either Matthew or I?

There were 3 options for the genetic testing that we were prepared for.  I hope I explain them correctly (and once again forgive me because I'm trying to write them in the ways that I understand it!)

First Option

The INI1 suppressor was only absent in the tumor cells.  We were told that this was only about 2% likely.  The children that normally have this happen have rhabdoid tumors when they are older than 1, and they have the highest survival rates.  Since James' tumor came back so quickly after the resection, and because he was 7 and a half months at the time of his diagnosis, this seemed unlikely.

Second Option

The INI1 suppressor is absent in all of James' cells.  Somehow this happened at conception and for some reason the sequence of proteins, etc. was interrupted causing this complete genetic mutation.

Third Option

Either Matthew or I are missing the INI1 suppressor in our genetic make up and passed it along to James.  If option 2 was true, then the lab will test the samples that Matthew and I submitted to see if either of us is missing the gene.  If one of us is found to be missing INI1, then any future children we would have would have a 50% chance of inheriting this suppressor and most likely would develop a rhabdoid tumor as well.

We were prepared for option 2.  We knew option 3 was a possibility, albeit small.  All week I had been expecting the results and by the end of the week I had convinced myself that I had passed along the gene deletion to James and I had caused him to get the tumor.  (It was a really bad week which I will write about later).

So Friday night Children's called to tell me the news.  Sweet Megan, who is a geneticist, stayed late and tracked down the director to the outside lab to get the results (we had been having delays all week).  She knew how nervous I was about the results, and I am just so thankful that she stayed late (On a FRIDAY) to find out.

James' tumor results came back NORMAL.  It was option 1.  There was one cell is in brain that mutated and caused this terrible, awful tumor.  To say I was shocked would be an understatement.  James was born absolutely perfect. 

I thought that this was the option I wanted- and its true that it is good news.  I don't know how I would have lived with the guilt if I had passed it on to him.  Or if it had happened at conception I would have come up with a way to blame myself. 

But now they have no clue why this one cell in his brain would mutate and do this.  No earthly idea.  And in some ways that is harder because there is no cause.  It's just a fluke. 

Flukes are hard- but it would be worse if I had given it to him.  So I am thankful for that!  I'm really interested in genetics now, maybe I will find out why cells do this!