Pathology in Marfan syndrome ?

Ans. is 'a' i.e., Fibrillin I o Marfan syndrome is an autosomal dominant disorder due to mutation in fibrillin-1 gene on chromosomal 15.Fibrillin-1 is a part of elastic fibres, thus defect in fibrillin-1 affects following systems:-1) Skeletal abnormalities: Tall with thin built; arachnodactyly (long and slender fingers and hand, spider like); decrease in upper segment: Lower segment body ratio (i.e. lower limbs are proportionately more lengthened); scoliosis and kyphosis; pectus excavatum and pectus craniatum; Hypermobility (laxity) of joint with hyperextensibly; high arched palate and dolicocephalic skull.2) CVS abnormalities : Mitral valve prolapse causing mitral regurgitation; aortic aneurysm begning at base of aorta and involving ascending aorta; cystic medial necrosis causing dissection of aorta (most common cause of death).3) Ocular abnormalities: Ectopia lends (with bilateral superolateral lens dislocation), elongated eyeball.4) Others: Spontaneous pneumothorax ; inguinal and incisional hernias.