The marfan syndrom variant is the most likely cause of your valve problems. The fact that you are tired with doing physical activity is a bit concerning and may mean that your valvular problems are more than just mild or moderate. Given that you are symptomatic, I think it is extremely important that you have further workup to find out why you feel this way. One way of doing it is by undergoing an exercise stress echocardiogram. It is possible that your functional capacity is affected by the valvular insufficiencies at which point you should have open heart surgery. that's what i would recommend at this point. Generally speaking, mild to moderate disease needs to be evaluated every 12 months or so. Again, since you are having symptoms those recommendations don't apply to you any more.