What Is Marfan Syndrome?
Marfan syndrome is a genetic disorder that affects the body's connective tissue. This vital tissue functions as an internal "glue and scaffolding," providing strength, support, and elasticity to structures like bones, blood vessels, eyes, and skin. Because connective tissue is present throughout the body, Marfan syndrome can cause a wide range of health issues, though the specific symptoms and their severity vary significantly from person to person.
The condition results from a mutation in the FBN1 gene, which provides instructions for making a protein called fibrillin-1. This protein is crucial for forming the elastic fibers that allow tissues to stretch and recoil. The genetic fault is most often inherited from a parent in an autosomal dominant pattern, meaning an affected individual has a 50% chance of passing it to each child. In about 25% of cases, the mutation occurs spontaneously in a person with no family history of the disorder.
Physical and Skeletal Symptoms
The effects of weakened connective tissue are often most visible in the skeletal system. While some signs may be present in childhood, they typically become more apparent during the growth spurts of adolescence.
Distinctive Stature and Limbs
Individuals with Marfan syndrome are often taller and thinner than their relatives. A classic sign is having disproportionately long arms, legs, fingers, and toes. This can result in an arm span that is greater than the person's height. The long, slender fingers and toes are a feature known as arachnodactyly, or "spider-like fingers."
Spinal and Chest Wall Deformities
Weakened connective tissue can affect the shape of the spine and chest. Scoliosis, a sideways curvature of the spine, is common and is monitored closely during periods of rapid growth. While mild curves may only require observation, more significant curves might need a brace or corrective surgery to prevent them from worsening and impacting lung function.
The breastbone (sternum) may also be affected, either sinking inward to create a concave chest (pectus excavatum) or protruding outward (pectus carinatum). A severely sunken chest can sometimes compress the heart and lungs, requiring surgery to relieve pressure and create more space for the organs.
Joint Hypermobility and Flat Feet
The ligaments that stabilize joints are also made of connective tissue. When these ligaments are too lax, it results in joint hypermobility, or "loose" joints. This unusual flexibility increases the risk of sprains, strains, and dislocations. Management often involves physical therapy to strengthen the surrounding muscles for better joint support. Many people also have flat feet because the ligaments are too weak to support the arch, which can be managed with supportive shoes and custom orthotics.
Facial and Dental Features
The disorder can influence the development of facial bones, often leading to a long, narrow face, a small lower jaw, and a high-arched palate. This can cause severe dental crowding, frequently requiring complex orthodontic treatment to ensure proper tooth alignment and oral health.
Cardiovascular Complications
While skeletal features are the most visible signs, the most serious health risks associated with Marfan syndrome involve the cardiovascular system. The same tissue weakness affects the body's largest artery, the aorta, as well as the heart valves.
Aortic Dilation and Aneurysm
The wall of the aorta, the main artery carrying blood from the heart, can lose its resilience and gradually stretch and widen. This process, known as dilation, most often occurs at the aortic root. If it widens significantly, it can form a bulge called an aneurysm. Because this widening is usually silent and has no symptoms, regular imaging tests like echocardiograms are essential to track the aorta's size and allow for intervention before it becomes dangerous.
Mitral and Aortic Valve Prolapse
The heart's valves can become weak and "floppy," preventing them from closing tightly. This most commonly affects the mitral valve, causing it to billow backward (mitral valve prolapse), and the aortic valve, which can leak and allow blood to flow backward (aortic regurgitation). Leaky valves force the heart to work harder, which may eventually lead to symptoms like fatigue, shortness of breath, or an irregular heartbeat.
Risk of Aortic Dissection
The most life-threatening complication is an aortic dissection, which occurs when a tear forms in the inner lining of the weakened aorta. Blood can then surge between the layers of the aortic wall, splitting them apart. This is a medical emergency that causes sudden, severe pain and requires immediate surgery. Proactive management, including medications to lower blood pressure and planned surgery to replace the aorta before it reaches a critical size, is focused on preventing a dissection.
Effects on Other Body Systems
The impact of faulty connective tissue extends beyond the skeleton and heart, affecting the eyes, lungs, and skin.
Vision and Eye Problems
The eyes are highly susceptible to the effects of Marfan syndrome. The most common ocular sign is ectopia lentis, a condition where the eye's lens shifts or becomes dislocated because the tiny ligaments holding it in place are too weak. This can cause severe nearsightedness, astigmatism, and other vision problems. Individuals are also at a higher risk for developing cataracts, glaucoma, and retinal detachment, making regular exams by an ophthalmologist crucial.
Lung Complications
The elasticity of the lung tissue can be compromised, making some individuals more prone to a spontaneous pneumothorax, or a collapsed lung. This happens when small air-filled blisters (blebs) on the surface of the lung rupture, allowing air to leak into the space around the lung. A collapsed lung causes sudden chest pain and shortness of breath and requires prompt medical attention.
Skin and Spinal Cord Issues
Many people with Marfan syndrome develop stretch marks (striae) on their skin, typically on the shoulders, hips, and lower back, even without significant weight changes. This reflects the skin's poor elasticity. A related issue can affect the dura, the connective tissue sac surrounding the brain and spinal cord. This sac can stretch and weaken, a condition called dural ectasia, which can sometimes cause back pain, headaches, or numbness in the legs.
