What is hirschsprung disease and what are the major symptoms?

Constipation: Hirschsprung's is being born with lack of certain nerves(nerves that cause relaxation) in the intestine. When these nerves are missing the affected portion of the intestine/colon cannot relax, therefore obstruction results.

Lack ganglion cells: Hirschsprung’s disease (congenital megacolon) is caused by failed migration of colonic ganglion cells in utero. Varying lengths of the distal colon are unable to relax, causing functional colonic obstruction.Can vary from very short segment to entire large bowel. Obstruction noted usually in infancy, Sometimes recognition is later due to intractable constipation.