NRG1 and schizophrenia: Yet, research to date has focused on the 5′-region of NRG1. This 5′-bias has been driven by the landmark study in 2002 conducted by Stefansson et al.,7 who identified a seven-marker schizophrenia-associated haplotype in the Icelandic population (HapICE) consisting of five SNPs and two microsatellites (478B14-848 and 420M9-1395) in the 5′-region of NRG1. As this milestone study, additional 5′-schizophrenia-associated haplotypes in the Irish (HapIRE)8 and Chinese (HapChina1-3)9 populations have been identified.