We went to Iowa City this week to meet with Corbin's team. We met with the research team to get him signed up to participate in the dystroglycanopathy study. While there we had him evaluated by a physical therapist. We received formal genetic counseling to give us information as far as how this disease is passed and how it may affect us if we choose to have more children. We learned amount a couple options we have if we choose to have more children in the future. We did a 6 month review with Corbin's neuromuscular Dr and discussed how things were going and developing. We also met with the physical therapist we have seen from the start in Iowa City and a member of the MDA (muscular dystrophy association) to discuss how they may be able to help us. As part of the research study, they did an ultrasound of different muscles to see how they change and develop. Our last stop was with the pediatric opthamologist. It was a very long day. By the end Corbin was beyond hungry and tired. This made the eye exam even more difficult than I had anticipated.
So the big question from everyone was what did we learn? We learned very little, but we also learned a lot. Makes sense right? The concrete good news we have is that Corbin's eyes look great. This was a big relief to us! The other stuff we learned (or didn't learn) is the not so concrete part.
At this point, we haven't received a formal diagnosis. They do believe he has one of the types of dystroglycanopathies. We learned this is a very rare form of muscular dystrophy. There are lots of types of muscular dystrophy caused by different proteins. All these proteins work together in the muscle cell. As I tried to describe before, the dystroglycan complex is responsible for attaching sugars to make the membrane of the cell strong. His dystroglycan complex isn't working correctly therefore the sugars aren't attaching. Because the membrane isn't as a strong, this allows cells to break apart and die.
The dystroglycan complex (and dystroglycanopathies) weren't discovered until about 15 years ago. Even at that time they didn't know it affect infants. To date there 18 known gene defects that cause this. In the last 2 years, I believe they said 5 of those genes were discovered. So while muscular dystrophy has been around for quite some time, this "branch" of muscular dystrophy is relatively new and rare. The study we signed Corbin up for in Iowa City so far has only 85 participants coming from all over the country as well as a couple from Canada.
The scientists in the lab are working on trying to find his mutated gene. When we did the muscle biopsy, they also took a skin biopsy. They can grow skin cells from this sample and continue to grow them as long as they need. (Pretty cool huh?!) This means they shouldn't need to take anymore DNA from him. It may take a few months for this process to complete. At the end, we may or may not know which gene still. Corbin has already had 14 of the 18 genes tested, but hopefully we find the cause. If all 18 genes check out okay, it means the mutated gene may not be discovered yet.
Until we find the mutated gene, Corbin's prognosis is unknown. We understand that even with a prognosis, Corbin is going to make his own path. He is going to do the things he is going to do. But, it may give us a sense of direction. If its a known gene, they may be able to tell us how other patients that had the same mutated gene progressed. This is why we are participating in the study. We want to help them collect data so that Corbin may help another family. There isn't a lot of information on the progression of this disease because is varies so much based on the mutated gene.
In order to help us understand this a little better, the Drs showed us slides of Corbin's muscle biopsy slides as well as comparing them to a control "normal" picture. I'll do my best to repeat how they described them.
The first picture below is of a control (regular) muscle and the second two are Corbin's muscles. Normally the cells would be similarly sized and close together. You can see Corbin has some irregular sized cells and they have a little more room between them than normal. You can also see clusters of purple. Those areas where the cell has broken apart and trying to regenerate.
.jpg)
This picture below is of a stain they use to look at specific proteins. In the control picture on the left you can see the green highlights the outside membrane of the cell. In the right pictures, there is areas with little or no green highlights. The pictures are the right are Corbin's. This shows that his cells don't have the correct amount of dystroglycan on the membrane.
.jpg)
I hope this helps a little bit. We don't know a lot more, but it helped clarify things a bit. Its so complex, and we will probably never fully understand it. Keep praying!
