Marfan Syndrome:

Marfan syndrome is a disorder of the connective tissue. Connective tissue provides strength and flexibility to structures throughout the body such as bones, ligaments, muscles, the walls of blood vessels, and heart valves.
Marfan syndrome affects most organs and tissues, especially the skeleton, lungs, eyes, heart, and aorta.
Signs and Symptoms:
Affected individuals often are tall and slender, have elongated fingers and toes, and have an arm span that exceeds their body height. Also unusually flexible joints, a long and narrow face, a highly arched roof of the mouth, crowded teeth, an abnormal curvature of the spine (scoliosis), and either a sunken chest or a protruding chest. About half of all people with Marfan syndrome have vision problems caused by a dislocated lens in one or both eyes, and most are nearsighted.
Most people with Marfan syndrome have abnormalities of the heart and the aorta. Leaks in valves that control blood flow through the heart can cause shortness of breath, fatigue, and an irregular heartbeat felt as skipped or extra beats. If leakage occurs, it usually affects the mitral valve, which connects two chambers of the heart, which regulates blood flow from the heart into the aorta. The aorta can weaken and stretch, which may lead to a bulge in the blood vessel wall. This can lead to a sudden tearing of the layers in the aorta wall. Aortic aneurysm and dissection can be life threatening.

Mutations in the FBN1 gene cause Marfan syndrome. The FBN1 gene provides instructions for making a protein called fibrillin-1. Fibrillin-1 binds to itself and other proteins and molecules to form threadlike filaments called microfibrils. Microfibrils become part of the fibers that provide strength and flexibility to connective tissue. Additionally, microfibrils hold molecules called growth factors and release them at the appropriate time to control the growth and repair of tissues and organs throughout the body. A mutation in...