Marfan's?

I am 27, 5'11, 130lbs, white male. I am tall, skinny, and cannot gain weight. My arms in particular are very skinny and gangly-looking. My arm span is two inches taller than my height, but the ratio is 1:03, short of the cutoff of 1:05 for Marfan's. I have a positive wrist test, but negative thumb test. I am wondering if I have Marfan's syndrome. This past year, for unrelated issue, I was seen by doctors and a cardiologist. I had several EKGs, a 48-hour holter monitor, chest x-rays, and a stress test. They all came back basically normal. I also had an echocardiogram, which I was told was also normal. I have never had any heart problems (knock on wood), other than occasional arrythmia and fast pulse. I would like an expert to give their opinion based on all of this? Do I have Marfans? Or just some of the characteristics? Can I rest easily that my aorta and heart are fine, based on all of the tests? This is driving me nuts and I would like some info! Thanks!