Clinical features: Marfan syndrome is one of the most common inherited disorders of connective tissue (the collection of cells that form the supporting and connecting structures of the body). The diagnosis is made clinically, based upon the family history and the observation of characteristic findings in a number of organs of the body, most importantly the eye, skeleton, heart and blood vessels. Strict diagnostic criteria have been established and should always be used when assessing individuals. Marfan syndrome is extremely variable and affected individuals may present at birth, in late childhood or in adult life. Major complications of the condition include dilatation and dissection of the aorta, lens dislocation and scoliosis. The management of the patient should involve a team, including a clinical geneticist, cardiologist, ophthalmologist and orthopaedic surgeon. With appropriate management of the cardiovascular manifestations, the life expectancy of someone with Marfan syndrome is close to that of the general population.
Incidence: The estimated prevalence of Marfan syndrome is between 1 in 5,000 and 1 in 10,000. The condition is equally common in all countries of the world and in all races.
Inheritance : Autosomal dominant. About 75% of individuals with Marfan syndrome have an affected parent, the remaining 25% have the condition as the result of a new mutation.
Gene : In most people with the Marfan syndrome the condition is caused by mutations in the fibrillin-1 gene on chromosome 15. More than 200 mutations have been described, no common mutation existing in any population. DNA testing is available either by direct mutation detection or DNA linkage studies, the mutation detection rate ranging from 70% to 93%. In a small proportion of people it is caused by mutations in the TGBR2 gene.
Prenatal diagnosis : Possible if a mutation has been identified in an affected individual or if appropriate DNA linkage studies have been undertaken in the family. If prenatal diagnosis is being considered, the family referral should be made to the local clinical genetics service prior to a pregnancy. This ensures family members are offered appropriate advice and investigations, to confirm whether or not prenatal diagnosis is possible.
Presymptomatic testing: It is essential that first degree relatives of an individual with Marfan syndrome are evaluated for signs of the disorder. DNA testing may be helpful in some families.
UK Support Group: Marfan Association UK Rochester House 5 Aldershot Road Fleet Hampshire GU51 3NG Tel: 01252 810 472 Fax: 01252 810 473 Answerphone: 01252 617 320 Web: www.marfan.org.uk
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