The Marfan syndrome is an autosomal dominant disorder with pleiotropic 
manifestations that involve the cardiovascular, ocular, and skeletal systems. 
Through a number of investigational approaches, the gene encoding for fibrillin, 
the FBN1 gene on chromosome 15, has been identified as the defective gene 
causing the Marfan syndrome. Fibrillin is the large glycoprotein with a 
repetitive domain structure and is a major protein component of microfibrils, a 
fibrillar system closely associated with elastin in connective tissue. 
Mutational analysis of defects in the FBN1 gene in patients with the Marfan 
syndrome has revealed that most mutations are private or unique in an affected 
individual or family. Analysis of fibrillin protein or gene defects in 
individuals with related phenotypes has revealed that a perinatal lethal 
syndrome, termed neonatal Marfan syndrome, is due to FBN1 gene mutations. In 
addition, fibroblast cell strains from a subset of patients with idiopathic 
scoliosis have fibrillin protein defects. Last, fibroblasts from calves affected 
with bovine Marfan syndrome display defects in the fibrillin protein. These 
studies have wide-ranging implications in the diagnosis, treatment, and 
prevention of Marfan syndrome and related disorders.