Anal atresia and Hirschsprung's disease
These are malformations of the end arms. In case of anal atresia the anus is nonexistent, often associated with a connection for defacation (fistula) to the genitals.
With Hirschsprung’s disease (megacolon congenicum), the rectum has no function, because the nerve supply is malformed. Both diseases require surgical correction and long-term medical attendance by the specialist.