Ans.202 *Hirschsprungs disease*

*Hirschsprungs disease*
Congenital aganglionic megacolon; colonic dilatation proximal to an aganglionic, contracted distal
colon and rectum; caused by gestational failure of neural crest cells to migrate to distal colon.
Autosomal dominant form associated with mutations of the RET gene, autosomal recessive form
associated with mutations of the endothelin-B-receptor gene.