Gene or protein deficient in marfan's syndrome-

Ans. is 'a' i.e., Fibrillin I Marfan syndromeo Marfan syndrome results from an inherited defect in an extracellular glycoprotein fibrillin - 1 on a chromosome - 15.o It has autosomal dominant inheritance.o PathogenesisA 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.A defect in fibrillin causes the defective function of elastic fibers.Microfibrils (containingfibrillin) are mainly distributed to Aorta, ligaments of joint and ciliary zonules of lens So, in Marfan syndrome these tissues are primarily affected.