My first year at college when I was picking my majors, I thought about what subjects I found most interesting and which subjects I tended to do well in and I ended up picking Genetics and Psychology. I had some ideas for how I would combine these areas, ranging from Genetics Counsellor to researching the genetics behind psychological conditions... to of course, where I ended up, teaching. I loved my majors and I loved learning about Genetics and Psychology and now I love teaching about them. I have always enjoyed being able to explain just how relevant the things I teach are to real life.
And then Genetics became a little bit too relevant. I think most people who are reading know that Max and Addie's kidney condition is genetic. But I do not think everyone really understands the genetics behind it. My dad routinely is shocked by the questions people ask him that show they don't understand the genetics of it. So I figured for today's post I would pop on my teacher hat and try and explain how they inherited Congenital Nephrotic Syndrome and then how that has affected all our family planning.
A single gene produces a protein called nephrin that enables you kidneys to correctly remove only waste. If you have that protein, your kidneys are like colanders with tiny holes that only filter out bad things. If you do not have that protein, your kidneys are like a collander with big giant holes that filter all of your good stuff out also. For that gene, there are two versions. Big N means you will make the protein and therefore have normal good kidneys. Little n means you cannot make the protein and therefore will have very bad kidneys. Every person has two copies of the gene- you got one from your mom and one from your dad. So you could be NN or Nn or nn. The big N is dominant and sufficient to make all the nephrin you need so you only need one big N to have totally completely normal kidneys. NN and Nn are both totally normal and you would never know the difference, unless you shipped your blood off and paid unreasonably amounts of money to be told which you are!
The difference with Nn is that they are called 'carriers' because they do have the bad version in there that they can pass on to their kids. Even being a carrier is very rare. It's slightly more common in Finland but here in America it's very unlikely. But as you are probably working out, it turns out Al and I are both Nn, we are both carriers. We had absolutely no idea. Our kidneys work perfectly. The fact that we happened to marry someone who is also a carrier is so very unlikely. In fact, so rare that the genetics team had to clarify multiple times that we could not possibly be related!
And then even with two carriers, the odds still favor having a healthy child. I have included a punnett square to try and demonstrate:
But basically 3 out of every 4 hypothetical children would get at least one big N and therefore be completely normal. Only 1 in 4 theoretically should get my little n and Al's little n and end up with bad kidneys. Mind you probability does not always predict reality. If you toss a coin 10 times, you should get 5 heads but you very well may not. So in theory, the odds that BOTH of our non-identical twins would end up being nn is only 1/16. But well that is exactly what happened.
Knowing their condition is completely genetic can be reassuring because it takes away any fear of blame. And it takes away uncertainty. With Max's neurological condition, we are so unsure of when, why, how things happened. But with their kidneys, we know exactly how it happened. And we know it was completely outside of our control and there is nothing we could have done differently. It just happened. And that can be such a relief to have such closure.
The difficult thing about it being a genetic condition is the impact it has had on our plans for our family. Al is one of four and has always wanted 4 children. I had only one sibling but he is so awesome that I always wanted more. So we had always planned to have 4 children. I had imagined being pregnant multiple times and having kids of different ages. But were we to have another child, it would have a 1/4 chance of having Congenital Nephrotic Syndrome. And while I feel tempted by that 75% chance of it not having bad kidneys, the 25% chance of having another child who would spend months in the NICU and need dialysis and ultimately transplant is just too high. As Al puts it, we're just out of kidneys to give. There are of course other options for building our family but they do not seem particularly feasible for us right now either. So by being a genetic condition, it has affected not only both of our children but it has affected our plans for potential other children as well...
BUT, and this is really important, we were given the most special wonderful blessing of all... TWINS! Had we had only one, we would not have had a second. And our one baby would never have had a sibling. God knew that we wouldn't be able to go through all this twice so He gave us two at once. We could do two babies in the NICU and 2 babies on dialysis when they happened at the same time. Having twins was the only way we ever could have handled two babies with this. It was the greatest blessing of our life that we got to have two children, that our babies have a sibling and we are thankful every day for our family. We may have thought we'd have more but now that we have our sweet boy and gorgeous girl, our family feels complete. So in the spirit of November and wanting every day to include what I am particularly thankful for... I am hugely thankful that God gave me two precious babies. And I'm also thankful that I did major in Genetics and do understand what all is going on. And that I can use my experiences to teach my students that yes, sometimes you do need to know Biology in the real world!