Phenotype and skeletal manifestations of Marfan Syndrome
Patients with MFS have a characteristic phenotype that is easily recognized: tall stature, long thin extremities (arm span/height ratio > 1.05 for white adults; may be lower in Asian and Afrocaribbean), dolichostenomelia (abnormally low upper/lower body segment ratio of <0.85 for white adults and <0.78 for black adults compared with normal ratios of ≥0.93 for whites and ≥0.87 for blacks), and diminished subcutaneous fat. The lower segment is defined as the distance from the top of the symphysis pubis to the floor in the standing position, and the upper segment is the height minus the lower segment (of note, severe scoliosis may skew these measurements). Skeletal manifestations include arachnodactyly (spider digits), pectus excavatum or carinatum, loss of thoracic kyphosis, scoliosis (>20 degrees), reduced elbow extension (<170 degrees), and pes planus. Facial manifestations include dolichocephaly (long, narrow face), malar hypoplasia, retrognathia, enophthalmos, and downslanting palpebral fissures.
