Marfan Syndrome (MFS) is an autosomal dominantly transmitted genetic disorder involving the connective tissue, characterized by arachnodactyly and cardiovascular abnormalities. The clinical spectrum of MFS is varied, ranging from asymptomatic condition to a severe state. Most commonly affected organs and organ systems include the skeletal system (long, slender, and loose jointed bones, scoliosis, pectus excavatum), eye (lens dislocation, retinal detachment, myopia, glaucoma, cataract, coloboma of iris), mouth and oral cavity (highly arched palate, crowded teeth, micrognathia) and nervous system (dural ectasia), among others. However, the most severe complications of the condition are its effects on the cardiovascular system. MFS causes the arterial walls to weaken, leading to its dilatation. Such a dilated artery can easily tear, lead to aortic dissection, and/or aneurysm. The aorta is fairly frequently affected. The heart valves may also be affected, especially the mitral and aortic valves causing blood to leak backwards through them. This may cause an enlargement of the heart, and/or mitral valve prolapse.
MFS is transmitted in an autosomal dominant manner. Interestingly, the disease is due to a single gene defect with full penetrance, although inter and intra familial variability is seen. About 75% of incidences of MFS is due to vertical transmission of a mutated gene, whereas the remaining is due to spontaneous mutations.
The causative gene is FBN1 (Fibrillin) gene, located on chromosome 15. This gene codes for the Fibrillin 1 glycoprotein, which plays an important role in the formation of the elastic fibers seen in connective tissues. When mutations are present in this gene, the protein may lose its function, thereby endangering the stability and support afforded by it, especially to the aorta, ligaments, and the eye.