<prompt> A young, tall, thin, male with arachnodactyly have ectopia lentis in both eyes. The most likely diagnosis isMarfans syndromeMarchesanis syndromeHomocystinuriaEhlers danlos syndrome  <response>: Arachnodactyly and ectopia lentis dislocation of the lens in tall thin male suggests Marfan;s Syndrome.It is a genetic disorder of the connective tissue of the bodyMutation in the fibrillary gene15 q 21.1Loss of fibrillary fiber base for deposition of elastinAlteration in connective tissue in various pas of the bodySkeletal changes:Patients are usually tall and have long limbsThe ratio of upper segment to lower segment is usually 2 SDs below the mean for age, race, and sexArachnodactylyfingers are long and slender, spider-likePectus excavatum, pectus carinatumScoliosis, kyphosisCardiovascular changes:Mitral valve prolapse, mitral regurgitationAoic aneurysm, aoic regurgitationOcular changes:Ectopia lentisMyopia due to elongation of the globeRetinal detachmentOthers:Spontaneous pneumothoraxInguinal and incisional herniasStriae over the shoulders and buttocksRef:Harrisons 18e p3212, 17e p2468-2469 