NRG1 and Hirschsprung disease: This cross-sectional study determined NRG1 type I (HRGα, HRGβ1, HRGβ2, HRGβ3, HRGγ, and NDF43 isoforms), type II and type III expressions in both ganglionic and aganglionic colons of 20 patients with HSCR and 10 control colons by real-time polymerase chain reaction (qPCR).