Aortic Root Dilation

I have a 13 year old son who has aortic root dilation, measuring 28 mm.  He is 59.5" tall, 125 lbs, has a solitary kidney and peanut allergy.  He is athletic, social, and is otherwise healthy.  I am taking him to see a geneticist at the end of the month to rule out Marfan Syndrome.  He does not present with any other Marfan symptoms other than his height and myopia.  What is usually done with an aortic root dilation of 28 mm?  Betablockers?  Are there any sports restrictions that he should be on?  He plays on a travel baseball team and he works out at home with light (5-10 lb) weights and cardio exercises.  What is the prognosis for aortic root dilation?  Thank you for your help.    

[LAWood]

A correction on my son's height, he is 69.5" tall.  

[kenkeith]

The major sign MS that would lead a doctor to consider an underlying condition is a dilated aorta or an aortic aneurysm. Sometimes, no heart problems are apparent until the weakening of the connective tissue in the ascending aorta causes an aortic aneurysm or even aortic dissection.  If and when a dilated aorta root is enlarged to an aneurysm, a doctor may advise no strenuous to prevent a dissection.

My report lists the normal measurement for aortic root to be 20-37 mm.  There are middle-aged individuals that are under a doctor's care and have been monitoring the aorta root size for years.  It appears when the size has increased to about 42 mm an operation begins to be considered.