What Is Marfan Syndrome? What Causes Marfan Syndrome?

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Main Category: Pediatrics / Children's Health
Also Included In: Cardiovascular / Cardiology
Article Date: 21 Feb 2010 - 0:00 PDT

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Marfan syndrome, also called Marfan's syndrome is a genetic condition that an individual inherits from a parent who also has the condition, or a parent with a faulty gene in their sperm or egg. The fault is carried by a gene called FBN1, which encodes a connective protein called fibrillin-1. The syndrome affects connective tissues - the fibers that help to provide support and structure to other tissue and organs.

Marfan syndrome can affect different parts of the human body, including the heart, blood vessels, bones, joints, and eyes. Sometimes, the lungs and skin are also affected..

Marfan syndrome has no impact on intelligence - it does not affect the patient's cognitive abilities.

The disease is named after Antoine Marfan (1858-1942), a French pediatrician. Marfan first described the syndrome in 1896 after observing distinctive features in a 5-year-old girl. Francesco Ramirez, Mount Sinai Medical Center, New York City, first identified the gene linked to the syndrome in 1991.

Marfan syndrome's effects on a human being can range from mild, moderate, severe to life-threatening. The most serious complications include damage to the heart valves and/or the aorta.

According to the National Health Service (NHS), UK, about 1 in every 5,000 British people has Marfan syndrome. It affects males and females equally.

Although it is mainly an inherited condition, in about 25% of cases no close relative with the same condition is identified. A person with Marfan syndrome has a 50% risk of passing it on to each offspring.

Although Marfan syndrome is incurable, there are therapies that can improve the patient's quality of life.

Individuals with Marfan syndrome tend to have long arms, legs and fingers. Often their arm-span is longer than their height.

According to Medilexicon's medical dictionary:

Marfan syndrome is a connective tissue multisystemic disorder characterized by skeletal changes (arachnodactyly, long limbs, joint laxity, pectus), cardiovascular defects (aortic aneurysm which may dissect, mitral valve prolapse), and ectopia lentis; autosomal dominant inheritance, caused by mutation in the fibrillin-1 gene (FBN1) on chromosome 15q.

Some individuals who are born with Marfan syndrome may be completely unaware until later on in life.

What are the signs and symptoms of Marfan syndrome?

A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.

As Marfan syndrome can affect varying parts of the body, it has no unique signs and symptoms; however, the following constellation of symptoms are usually sufficient to make a diagnosis:

• Very long limbs
• Long fingers/toes
• Dislocated lenses
• Aortic root dilation

Experts say there are several possible signs and symptoms that involve the skeleton, eyes and cardiovascular system. Signs and symptoms vary between individuals, from mild and limited to certain body parts, to severe and affecting several body parts. According to the National Health Service (NHS), UK, about 10% of cases have severe symptoms; which tend to worsen with age.

Skeleton (bones, teeth) signs and symptoms:

• Dolichostenomelia - long limbs. Wrists may be thin and weak.
• Arachnodactyly (achromachia) - very long and slender fingers/toes
• Pectus carinatum - protruding sternum (breastbone)
• Pectus excavatum - sternum caves in
• Extremely flexible joints
• Long and narrow face
• Small bottom jaw - can occasionally cause speech disorders
• Overcrowded teeth
• Most individuals are slim
• Flat feet
• Individuals are generally much taller than average height
• High palate - this can sometimes cause speech disorders
• Hammer toes
• Stooped shoulders
• Stretch marks on the skin not explained by pregnancy or weight gain
• Some individuals may experience pain in the joints, bones and muscles

People with Marfan syndrome have a higher risk of developing scoliosis (curvature of the spine), spondylolisthesis, and dural ectasia. Dural Ectasia is the widening or ballooning of the dural sac surrounding the spinal cord.

Eyes - signs and symptoms:

• Myopia - nearsightedness
• Astigmatism
• Exctopia lentis - dislocation of the crystalline lens; can affect just one or both eyes
• Early onset glaucoma
• Early cataracts
• Detached retina

Cardiovascular system - signs and symptoms:

• Undue fatigue
• Shortness of breath
• Palpitations
• Angina pectoris - pain radiates to the back, shoulder or arm
• Heart murmur
• Prolapse of the aortic and/or mitral valves (in the heart)
• Dilated aorta
• Aortic aneurysm
• Pregnancy - women at risk of aortic dissection (a tear in the wall of the aorta)

What causes Marfan syndrome?

A fault (mutation) in the FBN1 gene on chromosome 15 causes Marfan syndrome. Chromosome 15 encodes fibrillin-1, a type of glycoprotein. The Fibrillin 1 protein is vital for the formation of the extracellular matrix, including the biogenesis and maintenance of elastic fibers. The extracellular matrix is the defining feature of connective tissue in animals. In other words:

• A defective gene stops the body from producing Fibrillin 1.
• Fibrillin 1 is a protein. It helps give our connective tissue elasticity and strength.
• Connective tissue need elasticity so that we can move and flex.
• Connective tissue needs strength to support organs and various body parts.

Most healthy individuals have an abundance of Fibrillin in their eyes, bones and aorta. Individuals with Marfan syndrome have a lack of Fibrillin. So their bones grow longer than normal, and other symptoms and complications develop.

An autosomal dominant condition - even if one parent has Marfan syndrome, the child can inherit it. The majority of people with this syndrome inherited it form a parent. Approximately 1 in every 4 patients, though, has no parent with the condition (spontaneous Marfan syndrome). In cases of spontaneous Marfan syndrome something went wrong with the Fibrillin gene (mutation) in the egg or sperm of the parent - the parent did not have the syndrome, but their sperm/egg developed the genetic mutation.

How is Marfan syndrome syndrome diagnosed?

The doctor will study the patient's family and medical history. The physician will try to determine whether the patient has had any illnesses or symptoms that may be linked to Marfan syndrome signs.

The doctor will also listen to the patient's heart, check the skin for stretch marks, and observe the length and features of the patient's arms, legs, fingers and toes.

As signs and symptoms can vary enormously between cases, diagnosis may be challenging. Other conditions with overlapping symptoms, such as Ehlers-Danlos syndrome or Beals syndrome need to be ruled out.

When diagnosing children the doctor may refrain from a definitive diagnosis and wait till the child is a teenager, when signs and symptoms are more prominent.

Ghent Criteria - doctors often us a diagnostic criteria called Ghent Criteria, named after the Belgian city where doctors determined which features to include on the list. While some are easy to spot, others require diagnostic tests, such as:

• Echocardiogram - to check the state of the heart, valves and the aorta.
• EKG (electrocardiogram) - to check heart rate and rhythm.
• Slit lamp eye exam - to check for dislocated lenses.
• Imaging scans - such as a CT or MRI scan, to check the lower back for signs of dural Ectasia.

What is the treatment for Marfan syndrome?

Marfan syndrome is incurable, however, various therapies are available today to alleviate symptoms and minimize or prevent possible complications. The doctor will develop an individualized treatment program, the details of which depend on which body parts and systems are affected.

• Skeletal system (bones and joints) - the patient needs to be regularly evaluated so that any changes in the spine or sternum (breastbone) are detected, especially when the individual is a child and is still growing. It is important that abnormalities are treated promptly, because sometimes they can undermine the proper functioning of the heart and lungs. If necessary an orthopedic brace, or even surgery may be required.
• Ocular (eyes) - the patient should have regular eye exams so that any vision problems are detected and treated immediately. According to the National Marfan Foundation, most problems can be corrected with glasses (spectacles) and lenses. Sometimes the patient may have to undergo corrective surgery.
• Cardiovascular system (blood vessels and the heart) - the patient will also need regular assessments of the aorta and heart function. It is important to detect and treat any problems early, in order to prevent complications. The National Marfan Foundation advises patients with heart problems to wear a medical alert bracelet and to go straight to hospital if any chest, back or abdominal pain is felt.
  
  Beta-blockers may be prescribed for heart valve problems. Sometimes surgery is needed to repair the aorta or replace a heart valve. Prompt surgical intervention is an important preventive measure against possible aortic dissection (tear or rupture of the wall of the aorta).
• CNS (central nervous system) - if the covering of the spinal cord becomes inflamed (dural ectasia) the patient may need medication for symptoms of pain.
• Physical activity - as patients tend to be tall they may be encouraged to join sports teams. This may be dangerous if the sport involves physical contact. It is important to ask your doctor what sports are suitable for you or your child.

Written by Stephanie Brunner (B.A.)
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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