FBN1 and Marfan syndrome: Mutations in fibrillins (fibrillin-1 or fibrillin-2) lead to heritable connective tissue disorders known as fibrillinopathies such as Marfan syndrome (MFS), ectopia lentis (EL), Weill–Marchesani syndrome (WMS), MASS syndrome (Mitral valve prolapse, Aortic root diameter at upper limits of normal for body size, Stretch marks of the skin, and Skeletal conditions similar to Marfan syndrome), Shprintzen–Goldberg syndrome (SGS), and acromicric (AD) and geleophysic (GD) dysplasias.