Now get ready for your biology lesson for the day. :)
X-linked SCID usually only affects males, and is passed on from the mother. A female has 2 X chromosomes, one from Mom and one from Dad. If Mom passes on a defective X, then the unaffected X from Dad will fill in the bad parts of the X from Mom. She then becomes a carrier of SCID, which she can pass on to her kids. A male has 1 X from Mom and 1 Y from Dad. So if Mom passes on a bad X, then the Y from Dad cannot fix the bad X. That's why it usually only affects males. However, there must be the rare case in which a man who has been treated for SCID has a baby with a woman who is a carrier of SCID. Then they could each pass on a bad X, and have a girl who has X-linked SCID.
It really doesn't matter what form of SCID Cael had. The treatment for all forms of SCID is to get a new immune system by way of a stem cell transplant.
In Texas, where Cael was born, they are going to be including a screening for PIDD (primary immune deficiency disease, which includes SCID) in the newborn screening starting next month. I don't know how many other states have this test or will be incorporating this test soon, but it seems like one that, if included, would help save so many families a lot of time in the hospitals and a lot of stress dealing with infections and illnesses.
What are the odds of a stem cell transplant successfully treating SCID? Will he require more than one transplant in his lifetime?
ReplyDeleteIf the baby is less than 3 months old, and hasn't had any infections, the success rate is about 98%. The older they are, the more infections, the lower the success rate. According to primaryimmune.org (which is one of the best sources for information about primary immune deficiency, including SCID), the overall success rate over the last 30 years is 60-70%. We are at a hospital that has a LOT of experience. I'm hoping that will help with those odds.
ReplyDeleteThe idea is that the stem cell transplant will give him a brand new immune system. He will require all immunizations again, from the birth ones, all the way up to his age. They will do those all over time. As long as the cells engraft as they should, he should never need anything else, but they will follow up with him for the rest of his life to make sure things are staying the way they should. I have heard of some needing multiple transplants, but the donor for Cael is a very good match, so hopefully it engrafts well and he doesn't have any problems in the future.
Hi Sarah.. came across your blog and cael's facebook page.. i have to say that cael is a very brave boy given what he has gone through till now.. and a stem cell transplant now even.. i am a nurse from singapore and i work in an adult hematology high dependency unit and we get lots of patients coming in for stem cell transplant too..
ReplyDeleteWill continue to visit your facebook page and blog and all the best to cael. Stay hopeful and cheerful. How you all feel can influence cael and in turn play a big part in the outcome of it all.