Marfans Syndrome, Marfan's, Marfan Syndrom, Marfin
Marfan syndrome is a heritable condition that affects the
connective tissue. The primary purpose of connective tissue is to hold
the body together and provide a framework for growth and development. In
Marfan syndrome, the connective tissue is defective and does not act as
it should. Because connective tissue is found throughout the body,
Marfan syndrome can affect many body systems, including the skeleton,
eyes, heart and blood vessels, nervous system, skin, and lungs.
Marfan syndrome affects men, women, and children, and has
been found among people of all races and ethnic backgrounds. It is
estimated that at least 1 in 5,000 people in the United States have the
disorder.
Marfan syndrome affects different people in different
ways. Some people have only mild symptoms, while others are more
severely affected. In most cases, the disorder progresses as the person
ages. The body systems most often affected by Marfan syndrome are:
- Skeleton--People with Marfan syndrome are typically very
tall, slender, and loose jointed. Since Marfan syndrome affects the
long bones of the skeleton, arms, legs, fingers, and toes may be
disproportionately long in relation to the rest of the body. A person
with Marfan syndrome often has a long, narrow face, and the roof of
the mouth may be arched, causing the teeth to be crowded. Other
skeletal abnormalities include a sternum (breastbone) that is either
protruding or indented, curvature of the spine (scoliosis), and flat
feet.
- Eyes--More than half of all people with Marfan syndrome
experience dislocation of one or both lenses of the eye. The lens may
be slightly higher or lower than normal and may be shifted off to one
side. The dislocation may be minimal, or it may be pronounced and
obvious. Retinal detachment is a possible serious complication of this
disorder. Many people with Marfan syndrome are also nearsighted
(myopic), and some can develop early glaucoma (high pressure within
the eye) or cataracts (the eye's lens loses its clearness).
- Heart and blood vessels (cardiovascular system)--Most
people with Marfan syndrome have abnormalities associated with the
heart and blood vessels. The valve between the left chambers of the
heart is defective and may be large and floppy, resulting in an
abnormal valve motion when the heart beats. In some cases, the valve
may leak, creating a "heart murmur," which a doctor can hear with a
stethoscope. Small leaks may not cause any symptoms, but larger ones
may cause shortness of breath, fatigue, and palpitations (a very fast
or irregular heart rate). Because of faulty connective tissue, the
wall of the aorta (the large artery that carries blood from the heart
to the rest of the body) may be weakened and stretch, a process called
aortic dilation. Aortic dilation increases the risk that the aorta
will tear (aortic dissection) or rupture, causing serious heart
problems or sometimes sudden death.
- Nervous system--The brain and spinal cord are surrounded by
fluid contained by a membrane called the dura, which is composed of
connective tissue. As people with Marfan syndrome get older, the dura
often weakens and stretches, then begins to weigh on the vertebrae in
the lower spine and wear away the bone surrounding the spinal cord.
This is called dural ectasia. These changes may cause only mild
discomfort or may lead to radiated pain in the abdomen or to pain,
numbness, or weakness of the legs.
- Skin--Many people with Marfan syndrome develop stretch
marks on their skin, even without any weight change. These stretch
marks can occur at any age and pose no health risk. However, people
with Marfan syndrome are also at increased risk for developing an
abdominal or inguinal hernia where a bulge develops that contains part
of the intestines.
- Lungs--Although connective tissue abnormalities make the
tiny air sacs within the lungs less elastic, people with Marfan
syndrome generally do not experience noticeable problems with their
lungs. If, however, these tiny air sacs become stretched or swollen,
the risk of lung collapse may increase. Rarely, people with Marfan
syndrome may have sleep-related breathing disorders such as snoring or
sleep apnea (a sleep disorder characterized by brief periods when
breathing stops).
Marfan syndrome is caused by a defect (mutation) in the
gene that determines the structure of fibrillin, a protein that is an
important part of connective tissue. A person with Marfan syndrome is
born with the disorder, even though it may not be diagnosed until later
in life. Although everyone with Marfan syndrome has a defect in the same
gene, the mutation is specific to each family and not everyone
experiences the same characteristics to the same degree. This is called
variable expression, meaning that the defective gene expresses itself in
different ways in different people. Scientists do not yet understand why
variable expression occurs in people with Marfan syndrome.
The defective gene can be inherited: The child of a person
who has Marfan syndrome has a 50 percent chance of inheriting the
disease. Sometimes a new gene defect occurs during the formation of
sperm or egg cells, but two unaffected parents have only a 1 in 10,000
chance of having a child with Marfan syndrome. Possibly 25 percent of
cases are due to a spontaneous mutation at the time of conception.
There is no specific laboratory test, such as a blood test
or skin biopsy, to diagnose Marfan syndrome. The doctor and/or
geneticist (a doctor with special knowledge about inherited diseases)
relies on observation and a complete medical history, including
- information about any family members who may have the disorder or
who had an early, unexplained heart-related death
- a thorough physical examination, including an evaluation of the
skeletal frame for the ratio of arm/leg size to trunk size
- an eye examination, including a "slit lamp" evaluation
- heart tests such as an echocardiogram (a test that uses ultrasound
waves to examine the heart and aorta).
The doctor may diagnose Marfan syndrome if the patient has
a family history of the disease and there are specific problems in at
least two of the body systems known to be affected. For a patient with
no family history of the disease, at least three body systems must be
affected before a diagnosis is made. Moreover, two of the systems must
show clear signs that are relatively specific for Marfan syndrome.
In some cases, a genetic analysis may be useful, but such
analyses are often time consuming and may not provide any additional
helpful information. Family members of a person diagnosed with Marfan
syndrome should not assume they are not affected if there is no
knowledge that the disorder existed in previous generations of the
family. After a clinical diagnosis of a family member, a genetic study
might identify the specific mutation for which a test can be performed
to determine if other family members are affected.
Because a number of body systems may be affected, a person
with Marfan syndrome should be cared for by several different types of
doctors. A general practitioner or pediatrician may oversee routine
health care and refer the patient to specialists such as a cardiologist
(a doctor who specializes in heart disorders), an orthopaedist (a doctor
who specializes in bones), or an ophthalmologist (a doctor who
specializes in eye disorders) as needed. Some people with Marfan
syndrome are also treated by a geneticist.
There is no cure for Marfan syndrome. To develop one,
scientists may have to identify and change the specific gene responsible
for the disorder before birth. However, a range of treatment options can
minimize and sometimes prevent complications. The appropriate
specialists will develop an individualized treatment program; the
approach the doctor uses depends on which systems have been
affected.
- Skeletal--Annual evaluations are important to detect any
changes in the spine or sternum. This is particularly important in
times of rapid growth, such as adolescence. A serious deformity can
not only be disfiguring but can also prevent the heart and lungs from
functioning properly. In some cases, an orthopedic brace or surgery
may be recommended to limit damage and disfigurement.
- Eyes--Early, regular eye examinations are key to catching
and correcting any vision problems associated with Marfan syndrome. In
most cases, eyeglasses or contact lenses can correct the problem,
although surgery may be necessary in some cases.
- Heart and blood vessels--Regular checkups and
echocardiograms help the doctor evaluate the size of the aorta and the
way the heart is working. The earlier a potential problem is
identified and treated, the lower the risk of life-threatening
complications. Those with heart problems are encouraged to wear a
medical alert bracelet and to go to the emergency room if they
experience chest, back, or abdominal pain. Some heart valve problems
can be managed with drugs such as beta-blockers, which may help
decrease stress on the aorta. In other cases, surgery to replace a
valve or repair the aorta may be necessary. Surgery should be
performed before the aorta reaches a size that puts it at high risk
for tear or rupture. Following heart surgery, extreme care must be
followed to prevent endocarditis (inflammation of the lining of the
heart cavity and valves). Dentists should be alerted to this risk;
they are likely to recommend that the patient be prescribed protective
medicines before they perform dental work.
- Nervous system--If dural ectasia (swelling of the covering
of the spinal cord) develops, medication may help minimize any
associated pain.
- Lungs--It is especially important that people with Marfan
syndrome not smoke, as they are already at increased risk for lung
damage. Any problems with breathing during sleep should be assessed by
a doctor.
Pregnancy poses a particular concern due to the stress on
the body, particularly the heart. A pregnancy should be undertaken only
under conditions specified by obstetricians and other specialists
familiar with Marfan syndrome and be followed as a high-risk
condition.
While eating a balanced diet is important for maintaining
a healthy lifestyle, no vitamin or dietary supplement has been shown to
help slow, cure, or prevent Marfan syndrome.
Being diagnosed and learning to live with a genetic
disorder can cause social, emotional, and financial stress. It often
requires a great deal of adjustment in outlook and lifestyle. A person
who is an adult when Marfan syndrome is diagnosed may feel angry or
afraid. There may also be concerns about passing the disorder to future
generations or about its physical, emotional, and financial
implications.
The parents and siblings of a child diagnosed with Marfan
syndrome may feel sadness, anger, and guilt. It is important for parents
to know that nothing that they did caused the fibrillin gene to mutate.
Parents may be concerned about the genetic implications for siblings or
have questions about the risk to future children. Some children with
Marfan syndrome are advised to restrict their activities. This may
require a lifestyle adjustment that may be hard for a child to
understand or accept.
For both children and adults, appropriate medical care,
accurate information, and social support are key to living with the
disease. Genetic counseling may also be helpful in understanding the
disease and its potential impact on future generations.
While Marfan syndrome is a lifelong disorder, the outlook
has improved in recent years. Early diagnosis and advances in medical
technology have improved the quality of life for people with Marfan
syndrome and lengthened their lifespan. In addition, early
identification of risk factors (such as aortic dilation) allows doctors
to intervene and prevent or delay complications. Advances being made by
researchers provide hope for the future. With early diagnosis and
appropriate management, the life expectancy for someone with Marfan
syndrome is similar to that of the average person.
Scientists are approaching research on Marfan syndrome
from a variety of perspectives. One approach is to better understand
what happens once the genetic defect or mutation occurs. How does it
change the way connective tissue develops and functions in the body? Why
are people with Marfan syndrome affected differently? Scientists are
searching for the answers to these questions both by studying the genes
themselves and by studying large family groups affected by the disease.
Newly developed mouse models that carry mutations in the fibrillin gene
may help scientists better understand the disorder. Animal studies that
are preliminary to gene therapy are also under way.
Other scientists are focusing on ways to treat some of the
complications that arise in people with Marfan syndrome. Clinical
studies are being conducted to evaluate the usefulness of certain
medications in preventing or reducing problems with the aorta.
Researchers are also working to develop new surgical procedures to help
improve the cardiac health of people with Marfan syndrome.
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