Tomuschat [66] has shown that the expression levels of CBS and CSE in smooth muscle, ICCs, platelet-derived growth factor-α receptor-positive cells, enteric neurons, and colonic epithelium were markedly decreased in HSCR specimens, indicating that mucosal integrity and colonic contractility may have been affected, thereby rendering patients with HSCR more susceptible to developing HAEC. The gene discussed is CBS; the disease is Hirschsprung disease.