Because an interaction of the NRG1 and GDNF signaling system can be supposed in the ENS, the idea of an altered NRG1 system in some GINMDs is supported by the observation of an altered GDNF system, as demonstrated so far not only for HSCR (Butler Tjaden and Trainor, 2013) but also for diverticular disease, where a lack of the neurotrophic factor GDNF and its receptors RET and GFRα1 was recently observed (Böttner et al., 2013). The gene discussed is NRG1; the disease is diverticular disease.