Marfan

Marfan Syndrome is a genetic condition that affects connective tissues, particularly the heart valves, aorta, and the eyes. People with Marfan Syndrome also tend to be tall, with long fingers and toes.

In the eye weakness and loss of the zonular ligaments that support the lens lead to lens dislocation (ectopia lentis) and reduced vision. Patients with Marfan Syndrome are also commonly highly myopic (although hypermetropia or far-sightedness can also occur), and have a substantially increased risk of retinal detachment, chronic glaucoma and early cataract. When the lens dislocates so much that glasses or contact lenses can no longer improve vision, surgery is an option. There are some controversies regarding surgical techniques and options for refractive rehabilitation after surgery, but two papers published this year describe significantly different rates of retinal detachment after surgery for Marfan, with a Chinese group reporting 11 Retinal Detachments in surgery on 64 eyes.

Marfan Syndrome was first described by Antoine Marfan, a French paediatrician, at the end of the 19th century. We now know it is caused by mutations in a gene called FBN1, which encodes fibrillin-1, a glycoprotein essential for the elastic fibres in connective tissues. The exact mechanism is not yet clear, but it looks as though fibrillin-1 prevents the accumulation of transforming growth factor beta (TGF-β), and it is likely that reduced fibrillin-1 activity in people with the FBN-1 mutation leads to accumulation of TGF-β, and that this in turn leads to the connective tissue changes of Marfan Syndrome.

When I trained in ophthalmology a combination of systemic signs was required for the diagnosis of Marfan to be made. Someone with ectopia lentis but no other problems was considered to have “isolated ectopia lentis”. We know that eye changes can occur before, and without, significant heart defects in people with Marfan, and few years ago the diagnostic criteria (the so-called Ghent Nosology) was changed so that people with ectopia lentis and either a family history of Marfan, or a FBN-1 mutation, can be diagnosed with the condition. This is important both for assessing their individual risk of developing complications, and for genetic counselling.

In Marfan Syndrome, early diagnosis can reduce the impact of the condition on vision, and reduce the likelihood of cardiac complications.