Marfan syndrome: everything you need to know about this genetic disease

skin hyperextensibility due to marfan syndrome

Le Marfan syndrome is a fairly common genetic disease. There is a one in two chance for a person to pass it on to their children. This syndrome is characterized by a connective tissue abnormality and manifests itself through different organs: eyes, bones, joints, heart... Discover in this article all you need to know about the Marfan's disease.

Definition of Marfan disease

Marfan syndrome or Marfan disease is an inherited disorder that affects connective tissue. One in 5000 people in the world suffers from this pathology. It can affect many organs and body systems including the eyes, bones, joints, lungs and central nervous system.

La Marfan's disease is transmitted in the autosomal dominant mode. In other words, there is a 50% chance that a parent who suffers from this disease will pass it on to their children.

With the advance of medicine today, an individual affected by this hereditary illness may have a life expectancy similar to that of a normal person.

What causes marfan syndrome?

THEorigin of Marfan's disease comes from a mutation of the coding gene responsible for the production of the fibrillin protein. The latter is greatly involved in the formation of connective tissue. It gives this support fabric its elastic and resistant properties.

In the majority of cases, the modified gene is the FBN1 located on chromosome 15 (15q21). There is, however, a rare form of Marfan's disease caused by the mutation of the gene TGFBR2.

The modification of fibrillin has an effect on the fibers and other components of the connective tissues. This leads to the weakening of the tissue in question. The latter becomes loose and ultimately breaks. Note that connective tissues are the support structures of the body. They hold the organs together and are interconnected.

The tissues that are altered are cartilage, tendons, bones, heart valves and blood vessels.

Is there a risk factor for this disease?

Having a parent who suffers from it is the main Marfan disease risk factor. It only takes one parent to carry the mutant gene to pass it on to their child. It is possible to detect this gene even if the child is still in the mother's womb in order to anticipate the disease.

Attention, a new mutation of the FBN1 gene is also possible in 20% of cases according to the national reference Marfan. Thus, the patient has no family history of Marfan syndrome.

What are the symptoms of this genetic disease?

The Marfan's disease symptoms can be observed in various parts of the body: eyes, bones, cardiovascular system, etc.

Symptoms of Marfan syndrome in the heart and blood vessels

Damage to the cardiovascular system is one of the serious complications of Marfan's disease. It is possible to observe multiple affections.

The fibers that make up the aorta may be affected by genetic modification. The wall of this large vessel can thus become fragile, leading to the infiltration of blood between the internal and external layer. This is called aortic dissection. It is a relatively painful and dangerous arterial pathology.

Indeed, this can lead to a tearing of the vessel or its dilation. The dilation of the aorta forms an aneurysm which is a therapeutic emergency. Rupture of an aortic aneurysm can be fatal given the extent of the haemorrhage. These problems are usually seen before the age of 10 as part of Marfan syndrome.

Aortic dissection is more risky during pregnancy. It will be necessary to anticipate complications thanks to a cesarean operation.

In Marfan's disease, the heart valves can also be affected. During a dilation of the caliber of the aorta, the aortic valve, located between the aorta and the left ventricle, can undergo a functional insufficiency. In other words, it no longer manages to correctly contain the blood ejected into the vessel after the phase of the contraction of the heart or the ventricular systole.

There is then a reflux of blood which returns to the ventricle during the relaxation phase. L'aortic insufficiency related to Marfan's disease occurs in 50% of children and 70% of adults.

Aortic regurgitation causes a decrease in the flow of perfusion to organs, especially those located on the periphery of the body. It is mainly manifested by fatigue and shortness of breath at the slightest effort.

The mitral valve can also be affected by this fibrous damage. It is the valve that separates the left atrium and the left ventricle. It may leak or prolapse backwards.

Symptoms of Marfan's disease at the musculoskeletal level

The people who suffer from Marfan syndrome have deformed bones and joints. They are generally taller than the average person their age.

The patient has long, thin fingers. The sternum, a bone in the middle of the thorax, can undergo raised or hollow deformation. There spine can bend forward, backward or sideways. The feet are flat and the knee deforms with a backward curvature.

Individuals with Marfan syndrome also have a thin layer of fat under the skin and a relatively flexible joint.

Symptoms of Marfan's disease in the lungs

Marfan's disease can manifest as emphysema. It is the presence of air bubbles in the lungs due to the destruction of the pulmonary alveoli. These bubbles can rupture and cause pneumothorax. It is the presence of air in the pleural cavity which is the dead space around the two lungs.

These disorders can manifest as pain and shortness of breath.

Symptoms of Marfan's disease in the eyes

The genetic disease also has repercussions on vision. It can affect the integrity of the lens of one or both eyes. The patient will have difficulty seeing at a distance.

Retinal detachment is also one of the effects of Marfan syndrome.

Symptoms of Marfan's disease in the spinal cord

The disease can cause an enlargement of the meninges: the sac that surrounds the spinal cord and the cbrain. We are talking about a dural ectasia. More common in the Lumbar spine, this disorder is responsible for a headache, lumbar pain (back pain) or neurological problems such as sphincter insufficiency (urinary or fecal leakage).

Diagnosis of Marfan syndrome

Le diagnosis of Marfan's disease is suspected in an abnormally tall and thin person. The doctor is more and more fixed in front of characteristic signs in particular the demonstrations of an attack of organs.

The diagnosis is more likely when there is a first-degree relative (father, mother, sister, or brother) with the disease.

To confirm the diagnosis, blood tests can be done to look for the mutated gene. In pregnant women, it is also possible to do an amniocentesis to detect the genetic anomaly.

Monitor genetic disease complications

It will be necessary to make a control every year to evaluate the complications of marfan's disease. The patient should therefore make a Echocardiography to analyze a problem with the heart valves or the aorta.

The doctor will also prescribe X-rays of the hands, chest, spine, feet and skull. An examination by the ophthalmologist is also necessary to anticipate ocular complications.

If new symptoms appear, the attending physician should be consulted as soon as possible.

The life expectancy of a person with Marfan syndrome

Before, people who suffer from this disease generally did not exceed the age of 45 years. Currently, these people have a life expectancy more or less identical to that of a normal, healthy person. This is mainly explained by the existence of modern means to prevent complications, in particular those affecting the aorta.

How to treat this disease linked to a genetic mutation?

there is no curative treatment to correct connective tissue abnormalities in Marfan's disease. Above all, care should be taken to prevent complications related to the syndrome.

Doctors prescribe beta blockers such as propranolol or atenolol to reduce heart rate and the force of contraction of the ventricles. This is especially useful to avoid the risk of aortic rupture and aneurysm. However, these conditions can be treated with cardiovascular surgery.

For pregnant women, the risk of rupture of the aorta is greater. It will be necessary to repair the injured vessel before conceiving a child.

Valve repair damaged by the fibrillin gene mutation can also be done through surgery.

For deformities in the spine, they can be treated by wearing a corset. It is also possible to resort to surgery if the curvature of the spine is too great.

To treat the dislocation of the retina related to marfan's disease, the ophthalmologist can resort to eye surgery for retinal repair.

References

https://www.msdmanuals.com/fr/accueil/probl%C3%A8mes-de-sant%C3%A9-infantiles/maladies-du-tissu-conjonctif-chez-l%E2%80%99enfant/syndrome-de-marfan

https://ressourcessante.salutbonjour.ca/condition/getcondition/syndrome-de-marfan

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