How Does This Happen...?

Alyssa and Jake knew that Hirschprung Disease didn't run in their families, so it was likely a sporadic genetic mutation. But how and when did it happen?




As we know, Hirschsprung disease results from the absence of nerve cells within the colon. During embryonic development, nerve cells inside the neural tube migrate downward toward to colon. These cells typically complete this migration by 12 weeks gestation. If the nerve cells fail to migrate through the entire colon to the end of the rectum, it results in clinical Hirschsprung disease.  

As the above image shows, the colon preceding the section lacking nerves becomes enlarged. As the fecal mass increases, the tissue of the colon becomes compressed and irritated. This is called enterocolitiis.  If they enterocolitis persists, the tissue may die. This can lead to a life threatening infection called necrotizing enterocolities.  Enterocolitis is fatal in up to 30% of cases and is the most common cause of death from Hirschsprung Disease.








From http://emedicine.medscape.com/article/929733-overview#a0104:
http://www.mountnittany.org/assets/images/krames/97523.jpg