<prompt> Ectopia lentis in a child is seen in which of the following diseases?SarcoidosisHomocystinuriaAlkaptonuriaUrea cycle defects  <response>: b. HomocystinuriaRef: Nelson 20e p 326Ectopia lentis is one of the features of Homocystinuria, where the direction of lens subluxation is infero-medial, unlike supero-lateral subluxation in Marfan syndrome. 