Was always tall but now almost 40 & am growing taller. What's wrong? No acromegaly symptoms other than height grow. Would Marfans been Dx by this age?

Taller @40 acromegal. When acromegaly begins at your age increase in height is uncommon because ends of bones have fused. How careful have you documented increase in height?
It looks like. it can be diagnosed. Check this link. http://www.ncbi.nlm.nih.gov/pubmed/3495711.