Where (what choromosome) is the defective gene located if u have marfan syndrome??? :~D?

Marfan syndrome is caused by mutations in one member of a pair of genes called the fibrillin genes. These genes are located on chromosome 15, one of the 23 pairs of human chromosomes. combination with the action of other genes, leads to the formation of faulty fibrillin.

Read more at: http://www.marchofdimes.com/pnhec/4439_1...

Marfan syndrome consists of connective tissue anomalies resulting in ocular, skeletal, and cardiovascular abnormalities (eg, dilation of ascending aorta, which can lead to aortic dissection). Diagnosis is clinical. Treatment may include prophylactic 尾-blockers to slow dilation of the ascending aorta or prophylactic aortic surgery.(Merck)
Marfan syndrome is caused by mutations in the gene fibrillin-1. Fibrillin-1 plays an important role as the scaffolding for elastic tissue in the body. Disruption of such scaffolding (by mutations in fibrillin-1) results in changes in elastic tissues, particularly in the aorta, eye, and skin. Mutations in fibrillin-1 also cause overgrowth of the long bones of the body, resulting in the tall stature and long limbs seen in Marfan patients.
Please see the web pages for more details on Marfan syndrome.

To be short and sweet:
Marfan syndrome is an autosomal dominant disorder that has been linked to the FBN1 gene on chromosome 15. FBN1 encodes a protein called fibrillin, which is essential for the formation of elastic fibres found in connective tissue. Without the structural support provided by fibrillin, many tissues are weakened, which can have severe consequences, for example, ruptures in the walls of major arteries.