A young, tall, thin, male with arachnodactyly have ectopia lentis in both eyes. The most likely diagnosis is

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 gene(15 q 21.1)Loss 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 sexArachnodactyly(fingers are long and slender, spider-like)Pectus excavatum, pectus carinatumScoliosis, kyphosisCardiovascular changes:Mitral valve prolapse, mitral regurgitationAoic aneurysm, aoic regurgitationOcular changes:Ectopia lentisMyopia (due to elongation of the globe)Retinal detachmentOthers:Spontaneous pneumothoraxInguinal and incisional herniasStriae over the shoulders and buttocksRef:Harrison's 18/e p3212, 17/e p2468-2469