I had joined a yahoo group for parents of children with HD and it seems like a lot were more like my son than what you are describing. My son is doing well now, but when he was a much younger he wasn't even on the charts for growth. From 9-15 months he gained 4 oz. He had a severe speech disorder, even dh and I had a hard time understanding him. He was in kindergarten and wearing 3t clothes still. He actually didn't start really gaining weight until we started seeing the chiropractor.
I'm just thankful that isn't what he has. I'm not thrilled about a gluten free life, but it helps 3 of my four children with various issues and I think it's helping me as well.
Serenity LDS mommy to 4 rambunctious kidlets