Fibrillin is a glycoprotein, which is essential for the formation of elastic fibres found in connective tissue.

Fibrillin-1 is a major component of the microfibrils that form a sheath surrounding the amorphous elastin. It is believed that the microfibrils are composed of end-to-end polymers of fibrillin. To date, 3 forms of fibrillin have been described. The fibrillin-1 protein was isolated by Sakai in 1986, and mutations in the gene have been linked to the Marfan syndrome. At present more than 100 different mutations have been described. Fibrillin-2 was isolated in 1994 by Zhang and is thought to play a role in early elastogenesis. Mutations in the fibrillin-2 gene have been linked to arachnodactily (which is also a clinical symptom of Marfan syndrome). More recently, fibrillin-3 was described and is believed to be located mainly in the brain.

Fibrillin-1 and Fibrillin-2 are encoded by two different genes, FBN1 and FBN2, localized on human chromosomes 15 and 5, respectively. Mutation at FBN1 would cause Marfan syndrome.

Structural proteins