<prompt> Total colonic aganglionosis is a variant of?Crohns diseaseUlcerative colitisHirschsprungs diseaseTropical sprue  <response>: Ans. is c i.e., Hirschsprungs disease Hirschprung disease Congenital aganglonic megacolon is caused by defective migration of neural crest into the mesodermal layer of gut. There is aganglionosis absence of ganglions in a portion of intestinal tract. Intestinal segment lacks both Meissner submucosal and Auerbach myenteric plexuses. Total colonic aganglionosis Zuelzer Wilson syndrome is particular variant of Hirschsprungs disease 5-8 cases in which aganglionic portion extends to entire length of colon. In rare cases aganglionosis may extent from duodenum to rectum. 