an autosomal dominant disorder (see dominant allele) of the connective tissue in the body, affecting the blood vessels, skeleton, and eyes. Common symptoms of the disorder include an unusually tall frame, long fingers and toes, loose joints, curvature of the spine, protruding breastbone (pectus carinatum), and dislocation of the lens of the eye. The aorta of the heart may also be enlarged, and there may be leakage in the aortal valve. [Antoine Bernard-Jean Marfan (1858–1942), French pediatrician]