Variants of Hirschsprung's disease Variants of Hirschsprung disease consist of a group of diseases clinically resembling Hirschsprung disease despite normal rectal biopsy results. These diseases composed of a small part of gastrointestinal neuromuscular pathologies. Gastrointestinal neuromuscular pathologies have been classified in "International London Classification" under the headings of Enteric Neuropathies, Enteric Myopathies and Enteric Mesenchymopathies. Among them Segmental aganglionosis, hypoganglionosis, hyperganglionosis, MMIHS and internal anal sphincter achalasia constitute variants of Hirschsprung disease.