Symptoms of Marfan syndrome: focus on the paediatric patient

Ocular Manifestations and Patient Management
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Cecità e Ipovisione

Introduction

Marfan syndrome is a rare hereditary connective tissue disease that causes changes in the eye, bone, heart, blood vessels, lungs and central nervous system.

Genetic causes

The Marfan syndrome or Marfan's disease is an autosomal dominant genetic disorder of connective tissue caused by mutations in the fibrillin-1 gene (FBN11).

Fibrillin-1 is a protein involved in the formation of elastic fibres in connective tissue and, for this reason, Marfan syndrome is characterised by the weakening of connective tissue.

Systemic involvement

The manifestations of Marfan syndrome affect multiple organs, including the musculoskeletal system, the skin, the cardiovascular system and the eye.

Musculoskeletal problems

Individuals with Marfan syndrome are taller than average compared to their peers and family members. They also have an arm span (the distance between the fingertips of both hands when the arms are open) that is greater than their height. The fingers are long and thin. Often, the chest bone (sternum) is deformed and pushed inwards or outwards. The joints may be very flexible.

Common are the flat feeta deformity of the knee joint that causes knee retroflexion, often accompanied by kyphosis with abnormal curvature of the spine (kyphoscoliosis) and hernias.

The subject generally has little subcutaneous fat. The palatine vault is often high.

Heart problems

The most dangerous complications are in the heart and lungs. The connective tissue of the aortic wall may be affected. The weakened wall can cause blood infiltration between the inner layers of the aortic wall (aortic dissection), which may tear, or a swelling of the artery (aneurysm) that can break. Sometimes these problems develop before the child is ten years old.

Pregnancy increases the risk of aortic dissection. The caesarean section (caesarean section) is often recommended to reduce this risk.

If the aorta gradually widens or dilates, the aortic valve, which connects the heart to the aorta, may start to leak (aortic regurgitation). Enlargement of the aorta occurs in the 50% of children and in the 60-80% of adults. The mitral valve, located between the atrium and the left ventricle, may leak (mitral regurgitation) or prolapse causing a reflux of blood into the left atrium (mitral valve prolapse).

Such heart valve alterations can impair the heart's ability to pump blood. Abnormal heart valves can also develop serious infections (infective endocarditis).

Lung problems

Air-filled bubbles (cysts) can form in the lungs. Cysts can rupture, causing air to enter the space surrounding the lungs (pneumothorax). These disorders can cause pain and shortness of breath.

Spinal cord problems

The lining surrounding the spinal cord may enlarge (dural ectasia). Dural ectasia is common in individuals with Marfan syndrome and most frequently affects the lower portions of the spine. It may cause headache, lower back pain or other neurological problems such as bowel or bladder weakness.

Eye involvement

Ocular involvement may be present in as many as 54% of patients with Marfan syndrome.

Joint events

The most common ocular manifestations include ectopia lentis (i.e. displacement of the lens of the eye from its normal position) and retinal detachment.

Less serious manifestations

Less serious consequences may include a decrease in corneal curvature, increased corneal astigmatism and myopia.

Diagnosis and the role of ophthalmologists

Ophthalmologists play a very important role in the detection of Marfan syndrome: the diagnosis is usually clinically based, but genetic tests are also available.

Symptoms in the paediatric patient

Knowledge of the symptoms of Marfan syndrome in children is still limited.

Studies show that children with this condition are at higher risk of developing ectopia lentismyopia and reduced visual acuity (low vision).

In particular, ectopia lentis is one of the main diagnostic criteria for Marfan syndrome, in children as well as adults, and occurs in the 49% of younger patients with the condition.

Myopia and corneal astigmatism are also typically present in children with this condition.

The eyes of affected children also appear to have a thicker lens than those of unaffected children.

Although not an absolute diagnostic criterion for Marfan syndrome in adults, reduced corneal curvature is characteristic of this condition, so it could be considered as a diagnostic criterion in children.

Reduction of central corneal thickness is commonly reported in adult patients and a recent study found it for the first time even in younger patients.

Children with Marfan syndrome also have lower intraocular pressure than healthy children and iridodontitis (a flickering of the iris that appears when the eye is moved).

Management of ocular manifestations in the patient with Marfan syndrome

Managing the symptoms of Marfan syndrome can be challenging.

Patients should be assessed by an ophthalmologist for a number of parameters, including intraocular pressure, the state of the crystalline lens, the state of the retina and optic nerve changes.

When subluxation of the crystalline lens occurs (whereby the natural lens loses its normal position and becomes dislocated), the first line of management is to correct the refractive error with glasses but, in more severe cases, removal of the lens is necessary.

In most cases, the implantation of a phakic lens (i.e. the insertion of a lens inside the eye, without removing the natural lens), a safe and effective means of visual rehabilitation, is sufficient.

After surgery, patients must be regularly followed up.

Patients with Marfan syndrome should also be prepared to seek emergency ophthalmological consultation if they see flashes or experience partial or complete loss of visual acuity.

Early intervention to treat possible retinal detachment can preserve the visual function of affected patients.

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