The diagnosis of Marfan syndrome requires a multidisciplinary assessment including clinical genetics, cardiology, ophthalmology, and radiology. It is caused by mutation in the fibrillin 1 gene on chromosome 15. Gene testing remains problematic, as current techniques fail to find a mutation in 10–30% of cases, while a small number of non-Marfan patients (often with MASS – mitral valve prolapse, mild non-progressive aortic dilatation, skin and skeletal features – phenotype) do have mutations. The diagnosis remains clinical and is based on the Ghent criteria. Beta-blockers or angiotensin-converting enzyme inhibitors slow the rate of aortic dilatation. Prophylactic aortic root surgery should be considered when the aortic root exceeds 5·5 cm at the sinus of Valsalva. Marfan patients require regular follow-up including aortic root measurement, usually by transthoracic echocardiography. Lens dislocation is not universal in Marfan, but expert ophthalmology assessment,
especially in childhood, is advisable. Arthralgia and other skeletal symptoms are common, and associated with joint hypermobility. Respiratory complications include recurrent pneumothorax and sleep apnoea. Patients should be advised to avoid contact sports and scuba diving. There is an increased risk of aortic dissection in pregnancy, particularly when the aortic root diameter exceeds 4 cm. Younger patients should be assessed in the neonatal period, pre-school, at age 10, and at age
18 if they have some Marfan features, but fail to meet the Ghent criteria by one system, or if they have a family history of Marfan syndrome.
