Marfans Syndrome Marfan syndrome is a rare hereditary disorder of connective tissue, which causes connective tissue to be weaker than normal. Connective tissue is the most abundant tissue in the body. It supports and protects various other tissues, is a vital component of all organs in the body, and provides strength and elasticity to blood vessels. Therefore, a disorder of connective tissue can cause a variety of abnormal conditions. For people with the Marfan syndrome, weak connective tissue causes problems of the skin, muscles, ligaments, heart, eyes, blood vessels, and bones. It is estimated that about one in 10,000 people has the Marfan