Marfan syndrome is caused by a defect, or mutation, in the gene that determines the structure of fibrillin-1, 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.
The defective gene that causes Marfan syndrome 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, making it possible for two parents without the disease to have a child with the disease. But this is rare. 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.
Although everyone with Marfan syndrome has a defect in the same gene, different mutations are found in different families, and not everyone experiences the same characteristics to the same degree. In other words, the defective gene expresses itself in different ways in different people. This phenomena is known as variable expression. Scientists do not yet understand why variable expression occurs in people with Marfan syndrome.
How Marfan syndrome diagnosed?
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 if 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 in making a diagnosis of
Marfan syndrome, 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.
Recently, doctors discovered a connective tissue disorder known as
Loeys-Dietz syndrome, which has several characteristics that overlap with those
of Marfan syndrome. When making a diagnosis, it is important to distinguish
between the two disorders: Loeys-Dietz is more likely to cause fatal
aortic
aneurysms, and treatment for the two is different. A diagnostic test for Loeys-Dietz syndrome is available.
A hernia is an opening or weakness in the muscular structure of the wall of the abdomen. This defect causes a bulging of the abdominal wall. Symptoms of a hernia include pain or discomfort and a localized swelling somewhere on the surface of the abdomen or in the groin area.
Palpitations are unpleasant sensations of irregular and/or forceful beating of the heart. Palpitations can be relieved in many patients by stress reduction, stopping cigarettes, and reduction of caffeine and alcohol.
Abdominal aortic aneurysm is a ballooning or widening of the main artery (the aorta) as it courses down through the abdomen. The most common cause of aortic aneurysms is
"hardening of the arteries" called arteriosclerosis.
Retinal detachment is the separation of the retina from its attachments to the underlying eye tissue. Symptoms of retinal detachment include flashing lights and floaters. Highly nearsighted young adults and those who've had cataract surgery are at higher risk for retinal detachment.
Sleep apnea is defined as a reduction or cessation of breathing during sleep. The three types of sleep apnea are central apnea, obstructive apnea (OSA), and a mixture of central and obstructive apnea. Central sleep apnea is caused by a failure of the brain to activate the muscles of breathing during sleep. OSA is caused by the collapse of the airway during sleep. OSA is diagnosed and evaluated through patient history, physical examination and polysomnography. There are many complications related to obstructive sleep apnea. Treatments are surgical and non-surgical.
Chest pain is a common complaint by a patient in the ER. Causes of chest pain include broken or bruised ribs, pleurisy, pneumothorax, shingles, pneumonia, pulmonary embolism, angina, heart attack, costochondritis, pericarditis, aorta or aortic dissection, and reflux esophagitis. Diagnosis and treatment of chest pain depends upon the cause and clinical presentation of the patient's chest pain.
Scoliosis causes an abnormal curvature of the spine. When the cause of scoliosis is unknown the disorder is described based on the age when the scoliosis develops (infantile, juvenile, or adolescent idiopathic scoliosis). In functional scoliosis, curvature develops due to a problem somewhere else in the body. With neuromuscular scoliosis, there is a problem when the bones of the spine are formed. Treatment typically involves observation, bracing, and surgery and is dependent upon the severity of the curvature.
Emphysema is a progressive disease of the lungs. The primary cause of emphysema is smoking. Alpha 1-antitrypsin deficiency is a rare disorder that has a genetic predisposition to emphysema. Aging, IV drug use, immune deficiencies, and connect tissue illnesses are also risk factors for emphysema. Emphysema is a subtype of COPD (chronic obstructive pulmonary disease, COLD). Symptoms include shortness of breath and wheezing. Management of symptoms may be achieved with medications, quitting smoking, pulmonary rehabilitation, or surgery.
Snoring, like all other sounds, is caused by vibrations that cause particles in the air to form sound waves. While we are asleep, turbulent air flow can cause the tissues of the nose and throat to vibrate and give rise to snoring. Any person can snore. Snoring is believed to occur in anywhere from 30% of women to over 45% of men. People who snore can have any body type. In general, as people get older and as they gain weight, snoring will worsen. Snoring can be caused by a number of things, including the sleep position, alcohol, medication, anatomical structure of the mouth and throat, stage of sleep, and mouth breathing.
A heart murmur is the sound generated when blood flow within the heart is not smooth. Causes of heart murmurs can be functional, congenital, or caused heart valve conditions. Symptoms of a heart murmur may be none, or may include chest pain, shortness of breath, and arm, leg, and ankle swelling. Treatment of a heart murmur depends on the cause.
Connective tissue disease is when the body's connective tissues come under attack, possibly becoming injured by inflammation. Inherited connective tissue diseases include Marfan syndrome and Ehlers-Danlos syndrome. Systemic lupus erythematosus, rheumatoid arthritis, scleroderma, polymositis, and dermatomyositis are examples of connective tissue diseases that have no known cause.
Sudden cardiac arrest is an unexpected, sudden death caused by sudden cardiac arrest (loss of heart function). Causes and risk factors of sudden cardiac arrest include (not inclusive): abnormal heart rhythms (arrhythmias), previous heart attack, coronary artery disease, smoking, high cholesterol, Wolff-Parkinson-White Syndrome, ventricular tachycardia or ventricular fibrillation after a heart attack, congenital heart defects, history of fainting, and heart failure, obesity, diabetes, and drug abuse. Treatment of sudden cardiac arrest is an emergency, and action must be taken immediately.
Aortic dissection is a small tear in the large blood vessel that leads from the heart and supplies blood to the body. There are two types of aortic dissection, type 1 and type 2. Signs and symptoms of aortic dissection include a tearing or ripping pain, nausea, sweating, weakness, shortness of breath, sweating, or fainting. Treatment depends on the type of aortic dissection, and the severity of the tear in the aorta.
Stretch marks occur in the dermis, the elastic middle layer of skin that allows it to retain its shape. When the skin is constantly stretched, the dermis can break down, leaving behind stretch marks.
Loeys-Dietz syndrome is a syndrome is an inherited genetic syndrome characterized by aortic aneurysms in children. Children with Loeys-Dietz syndrome are at a greater risk of dying from the aortic aneurysms, because the aneurysms are prone to rupture at a smaller size than other aneurysms. Physical characteristics of the syndrome include early fusion of the skull bones, widely spaced eyes, and split uvula or cleft palate. Treatment includes surgical repair fo the aneurysms.
Your health care provider may refer you to a genetic professional. Universities and medical centers also often have affiliated genetic professionals, or can provide referrals to a genetic professional or genetics clinic. Genetic counseling provides patients and family members the tools to make the right choice in regard to test for a disease or condition.
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