chapter  54
Marfan Syndrome
Pages 11

The penetrance of the fibrillin mutation is high and the phenotypic expression is extremely variable.To date, more than 500 different mutations involving the

fibrillin-1 gene have been identified, but no correlation between the specific type of fibrillin-1 mutation and the clinical phenotype has been recognized. In approximately 75% of cases, an individual inherits the disorder from an affected parent. The remaining 25% of cases result from de novo mutation.There is little prognostic information provided by the detection of a mutation beyond the available information provided from the patient’s own family history.Therefore, genetic testing is mainly used for adjunctive clinical diagnosis in selected cases.