Marfan syndrome

Marfan syndrome

Marfan syndrome

 

 

Marfan syndrome includes connective tissue anomalies that lead to impairment of the eyes, skeleton, and cardiovascular system. The diagnosis is clinical. Treatment may include prophylactic p-blockers to slow the expansion of the ascending aorta, or prophylactic operations on the aorta.

 

Type of inheritance is autosomal dominant. The main biomolecular defect is a consequence of the mutation of FBN-1, the gene coding for the glycoprotein fibrillin-1, which is the main component of microfibrils and helps fix cells to the extracellular matrix. The leading structural defect covers the middle aortic wall envelope. Rare variants are the result of mutations in the gene encoding fibrillin-2.

 

Marfan syndrome - symptoms and signs

 

 

The severity of the disease varies considerably. Patient height is higher than the average for their age and relatives; arm span exceeds height. Arachnodactyly is noticeable, often due to the symptom of the thumb.Deformations of the sternum — the keeled chest or the shoemaker’s chest — are common, as well as over-bending of the joints, curvature of the knee by bulging back, flat feet, kyphoscoliosis, and diaphragmatic and inguinal hernias. Subcutaneous fatty tissue is usually poorly developed. Palate is often Gothic.

 

Changes in the eye include lens ectopia and iridodiosis. The edge of the stationed lens can often be seen through the unexpanded pupil. High degree myopia and sometimes spontaneous retinal detachment can be noted.

 

The most severe complications are due to pathological changes in the root and ascending aorta. The middle wall of the aorta is affected mainly in areas experiencing the greatest hemodynamic load. The aorta progressively expands or sharply stratified starting from the coronary sinuses, sometimes in children under the age of 10 years. The aortic root expands in 50% of children and 60–80% of adult patients and may cause aortic regurgitation. Infective endocarditis may develop. Additional valves and chords can lead to prolapse of the mitral valve or regurgitation, which causes the appearance of a systolic click and late systolic noise.There may be polycystic pulmonary disease and spontaneous pneumothorax.

 

Clinical manifestations in patients with a mutation of the gene encoding fibrillin-2 include congenital arachnodacillus with contractures, hypermobility of the joints and malformation of the external ear.

 

Marfan's Syndrome - Diagnosis

 

 

Diagnosis can be difficult, as many patients have few typical symptoms and no specific histological or biochemical changes. Given this variability, diagnostic criteria are based on a combination of clinical data, as well as familial and hereditary history. Nevertheless, the diagnosis remains unclear in many cases of partial Marfan syndrome. Homocystinuria may in part resemble Marfan syndrome, but it can be distinguished by the presence of homocystine in the urine. Prenatal diagnosis using the FBN-1 gene mutation assay may be complicated by a low correlation between genotype and phenotype.

 

If the family / hereditary anamnesis does not support Marfan syndrome, the diagnosis requires the presence of large criteria in the two organ systems and the involvement of the third.Otherwise, if there is a mutation that is known to cause Marfan syndrome, one big criterion in one organ system and the involvement of the second organ system is necessary for diagnosis. Diagnosis of Marfan syndrome in a patient whose relative is suffering from this syndrome requires one large criterion in family history, one big criterion from one organ system and the involvement of the second. Small criteria are used only to assess the involvement of organ systems, and do not have an independent diagnostic value.

 

Adapted from: De Raere, A., Devereux, R.B., Dietz, N.S., et al .: Revised criteria for Marfan syndrome. American Journal of Medical Genetics 62: 417–426,1996; Loeys, V., Nuytinck L, Delvaux, I., De Bie, S., De Paepe, A. Archives of Internal Medicine 161: 2447-2454,2001.

All patients should routinely receive p-block-tori, which contributes to the prevention of cardiovascular complications. These drugs reduce myocardial contractility and pulse pressure and reduce the progression of aortic root dilatation and the risk of aortic dissecting aneurysm. Preventive surgery is suggested if the diameter of the aorta is more than 5 cm. Pregnant women are at particular risk of complications from the aorta; it is necessary to discuss the possibility of correcting changes in the aorta before delivery.Prevention of infective endocarditis is shown before invasive dental procedures, as well as invasive methods of examination of the gastrointestinal tract.

 

It is necessary to examine annually a patient with Marfan syndrome and evaluate changes in the cardiovascular system, skeleton and eyes. Together, these measures can improve the quality of life and reduce mortality; life expectancy increased from 33 years in the early 1970s to 61 years in 1996. Relevant genetic counseling is indicated.



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