Marfan Syndrome is an inherited disorder of connective tissue, and is caused by genetic mutations that result in the dysregulation of the proteins of the extracellular matrix (fibrillin). These extracellular matrix proteins are deposited throughout the body-aorta, cardiac valves, bones and joints, eyes, spine, lungs and lining of the spinal canal (dura). The diagnosis of Marfan Syndrome, therefore is made based on the clinical criteria, known as the Ghent criteria. The diagnostic criteria requires there to be two “major criteria” in two different systems (one of which can be family history), plus “involvement” of a third system. Major features are commonly seen in patients with Marfan Syndrome, but are uncommon in people without Marfan Syndrome; whereas “minor features” are common both in patients with Marfan Syndrome, but also in the general population. Alone, the presence of minor features does not indicate Marfan Syndrome.
The clinical evaluation includes:
Complete family history to identify additional relatives who have the signs and symptoms of Marfan Syndrome. Having a first-degree relative with Marfan Syndrome, carrying genetic markers consistent with Marfan syndrome or a mutation in a gene that causes Marfan Syndrome are major criteria in the Family History system.
Dilated pupil and slit lamp examination of the eyes. Dislocation or subluxation of the lens of the eyes is the major Ocular system criterion.
Skeletal survey with measurement of the height, arm span, upper and lower segments, and assessment of the breastbone (sternum), spine, feet, hands, elbows, hips, facial configuration and palate, and joints. The presence of 4 of 8 specific skeletal features indicates a major Skeletal system criterion.
Cardiovascular/aortic imaging study, such as transthoracic or transesophageal echocardiogram, cardiac MRI, cardiac CT, or catheterization with angiography of the aorta and heart. Dilation or a history of dissection in the portion of the aorta that exits the heart (ascending aorta) is the major Cardiac criterion. Mitral valve prolapse is a feature of Marfan Syndrome, however is found in up to 5% of the population, thus is considered a “Minor” feature.
In cases where there are several suggestive features of Marfan Syndrome, and it is difficult to decide if the person has Marfan Syndrome or not, imaging studies of the lumbosacral spine can be exceedingly helpful. In dural ectasia, the lining surrounding the spinal canal becomes weakened, leads to expansion of the lower spinal canal, and causing an abnormal ratio in the vertebra body (bony part of the spine) and the spinal canal (dura, spinal fluid, spinal cord). Lumbosacral spine MRI provides the most reliable images in the evaluation for dural ectasia.
Whenever patients do not meet clinical criteria for a Marfan Syndrome diagnosis, other possible disorders are considered. These include:
MASS-a syndrome includes one or more of the following- mitral valve prolapse, musculoskeletal features but inadequate for the Marfan diagnosis, myopia (without ectopia lentis), skin changes (stretchmarks), and mild aortic dilation
Homocystenuria-an enzyme deficiency that causes dislocated lenses in the eyes, mitral valve prolapse, increased tendency to form blood clots, and may include mild aortic dilation.
Familial thoracic aortic dilation and dissection, where affected individuals do not meet clinical criteria for Marfan Syndrome, but have ascending, arch, or descending thoracic aortic disease
Familial ectopia lentis-affected patients show ectopia lentis without skeletal, cardiovascular, skin, or pulmonary abnormalities.
Stickler syndrome is a disorder that causes ocular vitreoretinal degeneration, which is associated with retinal detachment, early onset glaucoma and cataracts, joint pain (arthritis of the large joints), mitral valve prolapse
Beal syndrome, marked by joint contracture deformities without ocular and cardiovascular involvement
Shprintzen-Goldber syndrome, marked by skeletal involvement, abnormal formation in the bones of the skull, and developmental delay
Loeys-Dietz syndrome, marked by aortic and/or arterial aneurysm/dissection, “forked” uvula, abnormal formation of the skull bones, and some structural deformities of the heart (congenital heart disease).
All patients with aortic and cardiovascular abnormalities require annual or biannual follow up including imaging of the cardiovascular system. Patients with ocular, orthopedic, pulmonary and neurological involvement also required follow up with experts in those fields.
Prevention of Aortic Dissection
Progressive aortic dilation increases the risk of dissection, a tear between the walls of the aorta, Aortic dissection is very serious and can be fatal. Our goal is to prevent aortic dissection by lowering the blood pressure transmitted to the aorta (medical therapy; avoidance of competitive sports), avoiding a blow to the chest (avoidance of contact sports like football and basketball) and surgery.
Beta blocker medications have been shown to reduce the RATE of aortic growth over time, and are considered and/or recommended when the diagnosis of Marfan Syndrome is made. Examples of beta blocker medications include: Toprol (metoprolol), Tenormin (atenolol), Inderal (propranolol), Corgard (nadolol).
Alternatives for patients intolerant to beta blockers (usually due to wheezing, coughing or asthma symptoms) include calcium channel blockers (verapamil), angiotensin receptor blocking agens (valsartan) or angiotensin converting enzyme inhibitors (lisinopril).
The goal of aortic root resection (removal of the aneurysm) is to prevent life threatening aortic complications such as aortic rupture or dissection. Surgical options each have advantages and disadvantages. Today, these include:
Aortic root replacement with aortic valve replacement
Using a human or animal tissue valve (no need for anticoagulation; less durable and will need to be replaced approximately 10-15 years)
Using a mechanical valve composed of manmade materials like plastics (requires life-long anticoagulation; very durable)
Aortic root replacement with aortic valve sparing
Where a tailored graft is fitted around the patient’s own aortic valve
Longevity is unknown because the surgical technique is in evolution; some patients have undergone this 15-20 years and continue to do well
The aortic valve must be competent (trivial or no leaking from the valve; the aortic valve must be normally formed)