Signs and symptoms
More than 30 signs and symptoms are variably associated with Marfan syndrome. The most prominent of these affect the skeletal, cardiovascular, and ocular systems, but all fibrous connective tissue throughout the body can be affected. Skeletal system
Most of the readily visible signs are associated with the skeletal system. Many individuals with Marfan syndrome grow to above-average height, and some have disproportionately long, slender limbs with thin, weak wrists and long fingers and toes. The Steinberg sign, also known as the thumb sign, is one of the clinical examination tests for Marfan disease in the hands. It is a clinical test in which the tip of the thumb extends beyond the palm when the thumb is clasped in the clenched hand.Besides affecting height and limb proportions, people with Marfan syndrome may have abnormal lateral curvature of the spine scoliosis, thoracic lordosis, abnormal indentation (pectus excavatum) or protrusion (pectus carinatum) of the sternum, abnormal joint flexibility, a high-arched palate with crowded teeth and an overbite, flat feet, hammer toes, stooped shoulders, and unexplained stretch marks on the skin. It can also cause pain in the joints, bones, and muscles. Some people with Marfan have speech disorders resulting from symptomatic high palates and small jaws. Early osteoarthritis may occur. Other signs include limited range of motion in the hips due to the femoral head protruding into abnormally deep hip sockets.
The seven new criteria can lead to a diagnosis:In the absence of a family history of MFS:

Aortic root Z-score ≥ 2 AND ectopia lentis
Aortic root Z-score ≥ 2 AND an FBN1 mutation
Aortic root Z-score ≥ 2 AND a systemic score* > 7 points
Ectopia lentis AND an FBN1 mutation with known aortic pathologyIn the presence of a family history of MFS (as defined above):

Ectopia lentis
Systemic score* ≥ 7
Aortic root Z-score ≥ 2Points for systemic score:
Wrist AND thumb sign = 3 (wrist OR thumb sign = 1)
Pectus carinatum deformity = 2 (pectus excavatum or chest asymmetry = 1)
Hindfoot deformity = 2 (plain pes planus = 1)
Dural ectasia = 2
Protrusio acetabuli = 2
pneumothorax = 2
Reduced upper segment/lower segment ratio AND increased arm/height AND no severe scoliosis = 1
Scoliosis or thoracolumbar kyphosis = 1
Reduced elbow extension = 1
Facial features (3/5) = 1 (dolichocephaly, enophthalmos, downslanting palpebral fissures, malar hypoplasia, retrognathia)
Skin striae (stretch marks) = 1
Myopia > 3 diopters = 1
Mitral valve prolapse = 1The thumb sign (Steinbergs sign) is elicited by asking the person to flex the thumb as far as possible and then close the fingers over it. A positive thumb sign is where the entire distal phalanx is visible beyond the ulnar border of the hand, caused by a combination of hypermobility of the thumb as well as a thumb which is longer than usual.The wrist sign (Walker-Murdoch sign) is elicited by asking the person to curl the thumb and fingers of one hand around the other wrist.