What are the symptoms? It is important to note that the range of complications caused by Marfan syndrome, and their severity varies considerably between individuals, even in the same family. Each family has different manifestations (symptoms) of the condition. These manifestations may include: CardiovascularAortic aneurysm (ballooning), aortic dissection (tears in the wall of the aorta), and mitral valve prolapse (a heart problem in which the valve that separates the upper and lower chambers of the left side of the heart does not close properly) – sometimes requiring surgical repair. For this reason, each person suspected of Marfan syndrome should have an echocardiogram (which is a harmless ultrasound picture of the heart and big blood vessels). Heart palpitations require an electrocardiogram (ECG) to define the type of arrhythmia, and determine whether medication is required. SkeletalScoliosis or kyphosis (forward bending curvature in the spine) and possibly loose painful joints, protruding or indented chest, long hands, feet, fingers and toes, and flat feet. EyesMyopia (shortsightedness), dislocation of the ocular lens (a part of the eye that allows fine tuning of vision), detachment of the retina (the light-sensitive screen which lines the back of the eye) and glaucoma. LungsAsthma, Pneumothorax (collapse of lung due to air leaking from the lungs into the chest cavity), bronchiectasis and emphysema. What are the causes? Marfan syndrome is a heritable disorder (meaning that it is passed from parent to child) of connective tissue, which is due to a mutation in the gene for fibrillin-1, located on chromosome 15. Fibrillin-1 is an important protein component of blood vessel walls, heart, eyes, tendons and ligaments, and lungs. Absent or impaired fibrillin-1 results in thinning and increased stretchiness of tissues. How is it diagnosed? Marfan syndrome is diagnosed when classical signs of weakness in at least two systems (heart, eyes, skeleton) are found. Diagnosis is made on the basis of family history, physical examination including slit lamp examination for possible dislocated lens, and echocardiogram. Linkage to the gene on chromosome 15 may be studied if affected family members in two generations are available. How is it treated? All aspects of Marfan syndrome are treatable. Beta-blockers are recommended when the aorta is seen to be actively dilating beyond the upper limits of normal on echocardiography. Aortic root replacement is recommended in an adult when aortic root diameter reaches 4.8cm, to avoid tearing of the aortic wall. Arrhythmia affects 40 per cent of patients, and specific medication is available. Dislocated lenses cause shortsightedness, which can be treated with contact lenses or eye glasses. Lenses can be removed, and replaced. Scoliosis presents in early puberty, and should be closely monitored, as bracing or surgery may be necessary. Loose painful joints may require joint supports, pain relief, arch supports, physiotherapy and limitation of sporting activities. Inheritance patterns and prenatal diagnosis Inheritance patternsMarfan syndrome is inherited in an autosomal dominant mode, with one affected parent in 75 per cent of cases. In 25 per cent of cases the condition occurs as the result of a new spontaneous mutation in the causative gene on chromosome 15. Prenatal diagnosisPrenatal diagnosis should be discussed with a geneticist prior to pregnancy. If the mutation has been identified in the affected parent, prenatal diagnosis may be offered at 11 weeks of pregnancy. If parents wish to ensure an unaffected baby, preimplantation genetic diagnosis is available privately or through the NHS. Is there support? Support for young people with Marfan syndrome is available from CRY (see entry Heart Defects).