My father has md non of us got it except my sister has partial cerebal palsy. My father is now 43 and has done things the drs told him he would never be able to accomplish, he plays guitar, he walks and does other things thought not possible. I understand as me and my 5 sibling had to take care of my father on a bad day such as massages to stimulate muscles in his legs etc......
My father has a form of md only known to 5-6 other people and therefore no studies have been done. Be happy that your son is living, if it wasnt for my father I wouldnt be alive at this day, my father is exceptionally brilliant and a stay at home dad. I dont pity him but I give him my respect for doing the stuff he does
good luck!!
Jess