Marfan’s syndrome is a genetic disorder of the connective tissue that causes excessively tall stature and long extremities. It is carried by the gene FBN1, which encodes the connective protein fibrillin-1, and is a dominant trait. The human genetic makeup contains a pair of FBN1 genes, so because of its dominance, inheriting one affected FBN1 gene from either parent will result in Marfan’s syndrome. It effects both males and females, and has no ethnic bias. It was named after Antoine Marfan, a French pediatrician, who described the disease in 1896 after noticing striking features in a five-year-old girl.
The disorder presents with a wide range of over thirty mild to severe symptoms. The leading symptoms, however, are of the skeletal system. People with Marfan’s tend to be abnormally tall with long, slender limbs and long fingers and toes. In addition to being long, the extremities can be disproportionate with thin, weak wrists. Curvature of the spine, called scoliosis, and indentation/protrusion of the sternum, called pectus excavatum/carniatum, are also common. Other possible skeletal anomalies include hyperflexibility of the joints, flat feet, stopped shoulders, and unexplained stretch marks on the skin.
Cardiovascular problems associated with Marfan’s include fatigue, shortness of breath, palpitations, and angina pectoris. More specifically, degeneration of the mitral or aortic valves will cause regurgitation. Patients have also had a dialted aorta or an aortic aneurysm. Pregnancy increases the risk of aortic dissection secondary to an aneurysm. While pulmonary symptoms are rare, it should be noted that spontaneous pneumothorax, or collapsing of a lung, is not uncommon. Patients may also have sleep apnea or idiopathic lung disease.
The disease process of Marfan’s syndrome causes the weakening of the connective tissue of the dural sac encasing the spinal cord, which is called dural ectasia. While this is not life-threatening, it does decrease the quality of life for a person with Marfan’s. Symptoms of dural ectasia include severe pain in the lower back, limbs or abdomen, as well as neurological deficits. Marfan’s syndrome can also cause serious damage to the eyes. Patients may have near- or farsightedness, along with astigmatism. Dislocation of the crystalline lens in one or both eyes also occurs, usually superotemporal.
In 1996, the diagnosis criteria for Marfan’s syndrome was agreed upon internationally. An official diagnosis combines the family history of the patient and a combination of major and minor indicators of the disorder, rare in the general population, that occur in one individual — for example: four skeletal signs with one or more signs in another body system such as ocular and cardiovascular in one individual.
There is no cure for Marfan’s syndrome, but life expectancy has increased and is now similar to that of the average person. Doctors prefer to address each issue as it appears while providing a general preventative medication to slow progression of the disease. Patients must be checked regularly by a cardiologist to monitor the heart valves and the aorta. Physiotherapy has also been proven to improve function, arm length, and life span.
Image Caption: Micrograph of myxomatous degeneration of the aortic valve. Credit: Nephron/Wikipedia (CC BY-SA 3.0)