MFS is caused by changes in the FBN1 gene located on chromosome 15. Genes are instructions for cells to make proteins in the body. MFS is the result of a change (mutation) in the FBN1 gene.
This gene controls the production of fibrillin-1, which is a very fine fibre that is found in connective tissue. Fibrillin fibres come together to form an elastic mesh which helps to support certain structures in our body, such as blood vessel walls and the lens of the eye.
Fibrillin-1 also regulates the activation of transforming growth factor beta (TGF-β) binding protein, which takes part in the regulation of many different cell functions and affects connective tissues throughout the body.
Everyone carries two copies of each gene, one inherited from each parent. MFS follows a dominant inheritance pattern, which means the presence of one faulty FBN1 gene can cause MFS.
If either parent has MFS, a child has a 50% chance of inheriting the disease.
Among people with MFS, about 75% of them would have inherited the genetic change from one of their parents. As some people with MFS may have a mild form of the disorder, the parent may not have been previously recognised as having MFS.
The other 25% of people with MFS have it because of a new mutation in the gene.
