Is It True That Dystrophin Helps Repair Or Grow Muscles?

I have heard that dystrophin helps to repair/grow muscles ? Is this true? and if So .. what types of food would be good to combine with P90X which is an exercise program that requires Dumbbells to be lifted.. etc.. I am 49 ..6 3 tall .. and am currently down to 246lbs ( was 354 when I started my weight loss .. with Weight Watchers.. but that only took me so far before I hit a wall.. and exercise had to be done. with a new program with P90X .. ) .. but want to help build up that muscle..