In marfan syndrome, the defect is in
Marfan syndrome
o Marfan syndrome results from an inherited defect in an extracellular glycoprotein fibrillin - 1 on a chromosome -15.
o It has autosomal dominant inheritance,
o Pathogenesis
o A defect in fibrillin affects the elastic recoil of extracellular connective tissue.

Elastic fibers consist of a central core made up of elastin, surrounded by a peripheral network of microfibrils that consists largely fibrillin.
The defect in fibrillin causes the defective function of elastic fibers.
Microfibrils (containing fibrillin) are mainly distributed to Aorta, ligaments of joint and ciliary zonules of lens → So, in Marfan syndrome these tissues are primarily of elected
Fibrillin II
Collegen
Fibrillin I
Elastin