the FBN1 gene. It has been shown that these people are also deficient in asprosin, a gluco-regulatory protein hormone which is the C-terminal cleavage product of profibrillin. The levels of asprosin seen in these people were lower than expected for a heterozygous genotype, consistent with a dominant negative effect. Diagnosis Diagnostic criteria of MFS were agreed upon internationally in 1996. However, Marfan syndrome is often difficult to diagnose in children, as they typically do not show symptoms until reaching pubescence. A diagnosis is based on family history and a combination of major and minor indicators of the disorder, rare in the general population, that occur in one individualfor example: four skeletal signs with one or more signs in another body system such as ocular and cardiovascular in one individual. The following conditions may result from MFS, but may also occur in people without any known underlying disorder. Aortic aneurysm or dilation Arachnodactyly GERD Bicuspid aortic valve Cysts Cystic medial necrosis Degenerative disk disease Deviated septum Dural ectasia Early cataracts Early glaucoma Early osteoarthritis Ectopia lentis Emphysema Iris coloboma Above-average height Heart palpitations Hernias High-arched palate Hypermobility of the joints Kyphosis (hunched back) Leaky heart valve Malocclusion Micrognathia (small lower jaw) Mitral valve prolapse Myopia (nearsightedness) Obstructive lung disease Osteopenia (low bone density) Pectus carinatum or excavatum Pes planus (flat feet) Pneumothorax (collapsed lung) Retinal detachment Scoliosis Sleep apnea Stretch marks not from pregnancy or obesity Teeth crowded "Narrow, thin face" Temporomandibular joint dysfunction (TMD) Revised Ghent nosology In 2010, the Ghent nosology was revised, and new diagnostic criteria superseded the previous agreement made in 1996. The seven new criteria can lead to a diagnosis: In the absence of a family history of MFS: Aortic root Z-score ≥ 2 AND ectopia lentis Aortic root Z-score ≥ 2 AND an FBN1 mutation Aortic root Z-score ≥ 2 AND a systemic score* > 7 points Ectopia lentis AND an FBN1 mutation with known aortic pathology In the presence of a family history of MFS (as defined above): Ectopia lentis Systemic score* ≥ 7 Aortic root Z-score ≥ 2 Points for systemic score: Wrist AND thumb sign = 3 (wrist OR thumb sign = 1) Pectus carinatum deformity = 2 (pectus excavatum or chest asymmetry = 1) Hindfoot deformity = 2 (plain pes planus = 1) Dural ectasia = 2 Protrusio acetabuli = 2 pneumothorax = 2 Reduced upper segment/lower segment ratio AND increased