This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
Hirschsprung disease is due to 
Select and explain. 
A. Failure of migration of Neural crest cells, B. due to loss of crypts, C. due to mucosa thickening, D. none
A: Failure of migration of Neural crest cells
Answer: A: Failure of migration of Neural crest cells 
Explanation: The enteric nervous system is the pa of the autonomic nervous system that directly controls the gastrointestinal tract. Derived from a multipotent, migratory cell population called the neural crest, a complete enteric nervous system is necessary for proper gut function. Disorders that arise as a consequence of defective neural crest cell development are termed neurocristopathies. One such disorder is Hirschsprung disease, also known as congenital megacolon or intestinal aganglionosis. Hirschsprung disease occurs in 1/5000 live bihs, and typically presents with the inability to pass meconium, along with abdominal distension and discomfo that usually requires surgical resection of the aganglionic bowel. This disorder is characterized by a congenital absence of neurons in a poion of the intestinal tract, usually the distal colon, due to a disruption of normal neural crest cell migration, proliferation, differentiation, survival and/or apoptosis. ref : harrisons 21st ed