Are any of the moms of boys with myotubular myopathy experiencing symtoms?
My mom had my brother and I’m pretty sure that she doesn’t have any symtoms.
MTM in the most common form is X-linked, meaning it’s carried on the X chromosome. Since females have two X chromosomes (XX), the X without the MTM gene compensates for the X with the MTM gene. Thus, the female carriers usually do not show any signs of the myopathy, although in some very rare cases they do. My grandmother, my mother, and I are all carriers who show no signs of this myopathy.
On the other hand, males are XY: they inherit the X chromosome from Mom and the Y chromosome from Dad. If Mom donates the carrier X to her son, which she has a 50/50 chance of doing, then he will not have a non-carrier X to compensate. Hopefully this clarifies why MTM X-linked shows up in boys but not women.
There are tons of women out there who are ‘manifesting carriers’- meaning that, even though they are carriers, they also begin manifesting the symptoms of the disease, as well. There are a few medical articles regarding this process, but I have found that there are a lot more manifesting carriers than the literature supports. Your best chance of finding this out is from talking with other moms/families affected by the disorder. It’s amazing how many similarities the women have in common! You can meet a lot more families affected by Myotubular Myopathy and Centronuclear Myopathy on the MTM Yahoo Group which can be found at the following link: http://health.groups.yahoo.com/group/Myotubular_Myopathy/?yguid=79231393
I am a mom of 2 daughters. I have the disease/symptoms and everything, but my daughters don’t.
My daughter and I, who are both carriers, have always been a little clumsy. I wouldn’t say that it’s had much effect on my life, but I know that my thigh muscles don’t respond to weight training as well as my other muscles and that I’ve always very slightly dragged one foot - not enough to slow me down, but enough that the sound of my footsteps is distinctive.
I can’t prove it, but I think these things are related to that one problematic X.
Julie