Marfan syndrome is a geneticdisorder that affects connective tissues, such as muscles, ligaments, bones,and blood vessels, due to a mutation of the FBN1gene.
1 FBN1 codes forfibrillin-1, a protein that makes up the fibers of connective tissues instructures called microfibrils. 2 Fibrillin-1 also stores growthfactors, such as transforming growth factor beta (TGF-), that areperiodically released for growth and repair.1 Whenthe FBN1 gene is mutated, fibrillin-1releases an increased amount of TGF-, which causescharacteristic symptoms such as elongated arms, legs, and fingers and tall bodytype.1 The mutation also leads to problems in the heart and bloodvessels due to weakened muscle fibers.2 Signs of the disease includecurved spine, chests that sink in or stick out abnormally, crowded teeth, andflat feet.1 Many affected individuals have eye problems, such as adegree of nearsightedness, dislocated lens, early glaucoma, and earlycataracts.1 Life-threatening symptoms, which can present right awayduring childhood or in some cases present later into adulthood, include aorticenlargement (expansion of the heart’s largest artery), risk of aorticdissection and aneurism, due to weakening of the aortic muscle, and heart valveleaks, which can cause shortness of breath, fatigue, and irregular heartbeats.2Marfansyndrome affects about 1 in 5,000 people, and has been diagnosed in males,females, and various ethnic groups.1 Mutations for the disorder areinherited in an autosomal dominant pattern, meaning that inheritance of onedefective allele will cause symptoms.2 The disorder exhibitsvariable expression, meaning it affects different individuals with varyinglevels of severity and can affect different parts of the body depending on thecase.1 Although the majority of cases are inherited, about 25% ofcases are the result of spontaneous mutations in the FBN1 gene.2
