Genetics

The word mutation is so ugly, isn’t it? And yet, we all have, existing within our cells, genes that have some sort of mutation. Maybe these changes only manifest themselves in things that are relatively benign, like having colour blindness or an exceptionally large nose. In other cases, changes in genes can be a little more serious, and people are born with chromosomal disorders, or extra digits, or club feet.

In Gavin’s case, he was born with a change to the hSNF5/INI1 gene in chromosome 22. This mutation can not be seen. It doesn’t manifest itself in any way, physically or cognitively, in his body.  He appears to be a perfectly normal little boy, except that this gene is now thought to be a tumour-suppressor gene. A change or deletion of this gene is strongly linked to AT/RT tumours, and other CNS tumours. In Gavin’s tumour, this gene was deleted, which is why the tumour grew out of control so quickly. Further genetic testing confirmed that he has a extra copy of this gene in every cell of his body, which is a germline mutation.

Very, very rarely, a parent can pass on this mutation to their child, although it would be unlikely that the parent would have grown to adulthood without ever having a malignant brain tumour of their own. Unfortunately, unlikely seems to rule our lives right now. I learned today that I too possess this mutation in every cell of my body, and that I passed it on to my son. We were told that the possibility existed that this would be so, but that it would be unlikely.

Again today I was forced to battle through that wave of nausea, fear, sadness, and yes, guilt that accompanies such horrendous news. I cannot say that I was entirely surprised. I had a pretty good feeling that this would be so, despite the odds, given my family history of brain tumours. Despite that, it is still very difficult news to handle, and obviously I’m still trying to process it.

The good news is that I made it to adulthood without ever developing a malignant CNS tumour.  Usually this mutation is associated with pediatric tumours. The bad news is that many with this mutation develop benign tumours called schwannomas, which is a medical condition which must also be handled, often with surgery. I’ve also been told that the chances of my also having schwannomas is unlikely, but possible. Within the next little while I’ll be having an MRI to determine if any tumour growth is already taking place. The power of positive thinking will have to guide me here, because unlikely seems determined to rule my fate.

The other unfortunate news is that this means that any other children we have would have a 50% chance of also having this mutation. We don’t like those odds, and knowing what we know, we could not possibly bring another child into the world aware that he/she would potentially have to undergo treatment. There still may be options for us to expand our family, but there are many things that need to be addressed first.

I don’t know what this means for the other members of my family yet. There will be more testing done on various relatives to determine who, if anyone, also has this same abnormality.

Life seems very unfair to me at the moment. Tomorrow will be my day for rallying and getting on with it. Tonight I feel betrayed by my genes.