What causes marfan syndrome?

Genetic mutation: Marfan syndrome is caused by a gene mutation (in the fbn1 gene). A mutation leads to defective, weakened connective tissue throughout the body. Symptoms show up in the parts of the body where shape and structural integrity relies a lot on the weakened type of connective tissue.

Fibrillin mutation: Classic Marfan syndrome is an autosomal dominant disease caused by a mutation in the fbn1 gene which codes for fibrillin-1, a component of connective tissue. Most people with Marfan syndrome have an affected parent, but about 25% of Marfan syndrome is caused by a spontaneous mutation of the fbn1 gene.