Nobody in both our family lines have m.d or any forms but both me and my child’s father have a gene that was passed to our 2nd son and he has spinal muscular atrophy type 3 never heard of it or know anything about it except what we learned about it through him going through from time diagnosis’s to now he was diagnosed at age 3 he’s 18 it’s so hard for me

I am the 5th member of my family to be diagnosed with a form of MD. My uncle and father were diagnosed in early 80s with LGMD and my father also had a possibility of having polymyositis along with LGMD. A cousin was said to have had a typical LGMD, my older brother was diagnosed with Inclusion Body Myo and his was thru muscle biopsy and I thru labs was first diagnosed with LGMD but my Dr did not feel that was right so she did a rest for VCP that came back positive for IBMPFD. Dr said it is rare but it's possible to have more than 1 form within a family.

So is it possible for my brother to have a different type as well?