If there is suspicion of marfan syndrome, how early should it be diagnosed? would early 20s be ok? also, would and ekg/echo reveal anything about it?

Early is better: Marfans can have effects on lens development at an early age - even before teens. Cardiac- and specifically aortic complications are the most worrisome however and can occur in the 20s. Echo may show some changes to the aortic root, but it is not a perfect study for this. Sometimes a trans-esophageal echo is needed where the ultrasound probe is placed through the mouth to get the view.

See below: Diagnosis after 20 is often more reliable due to symptoms that develop later, but it can be diagnosed before with certain criteria and genetic testing. Echo can help as well.