Identification of defects in the fibrillin gene and protein in individuals with the Marfan syndrome and related disorders.

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.