Neural crest cells are a population of stem cells that invade the embryo in early development. They play a big role in what you look like: the pigments of your eyes, of your skin, and the bone structure of your face are all neural crests. Inside your body, the neural crest will form the myelin sheath of your peripheral nervous system and the entire nervous system of your intestine, the so-called “second brain.”
Neurocristopathies are a range of pathologies resulting from defective neural crest migration. One of the most frequent ones is Hirschsprung disease; it affects 1 in 5,000 newborns. These babies lack a nervous system inside their colon because the neural crest cells didn’t make it all the way to the end of the digestive tract during embryogenesis. The condition is lethal if not surgically treated at birth and its causes remain unknown in more than half of cases.
Among the identified genes involved in Hirschsprung disease, one has stood out for more than half a century: the peptide endothelin 3. Mice and humans with genetic defects in either endothelin 3 or its receptor EDNRB develop the disease, in some cases accompanied with pigmentation or craniofacial defects.









