Marfan syndrome is a genetic condition that affects the body’s connective tissue which is the material that acts like “glue and scaffolding,” holding together and supporting organs, blood vessels, bones, and skin.

The condition is caused by a change in a gene called FBN1. This gene carries the instructions for making a protein called fibrillin-1, which is a key building block of connective tissue. When this protein doesn’t work properly, connective tissue throughout the body becomes weaker and more stretchable than it should be. Because connective tissue is present almost everywhere in the body, Marfan syndrome can affect several systems at once – most importantly the heart and blood vessels, but also the eyes, bones, joints, skin, and lungs.

It’s important to understand that Marfan syndrome is not caused by anything the person or their parents did during pregnancy or childhood. It is simply how a particular gene was inherited or, in some cases, how it changed spontaneously.