Lack of Associations of Neuregulin 1 Variations with Schizophrenia and Smooth Pursuit Eye Movement Abnormality in a Korean Population

Schizophrenia is a serious and disabling mental disorder with a high heritability rate. The human neuregulin 1 (NRG1) on 8p12 has been implicated as a candidate gene for schizophrenia. However, controversial results of the associations of NRG1 polymorphisms with schizophrenia and related phenotypes have been reported. In this study, four NRG1 single nucleotide polymorphisms, three in the promoter region, and one nonsynonymous in coding region, were genotyped in a total of 825 subject including 435 schizophrenia cases and 390 normal controls of Korean ethnicity. Although logistic association analysis of NRG1 polymorphisms and haplotypes with schizophrenia showed a nominal association in rs4623364G > C (P = 0.04), the significance disappeared after corrections for multiple testing (corrected P > 0.05). Additional case/control and multiple regression analyses in schizophrenia patients using a method that measures the smooth pursuit eye movement (SPEM) function globally based on natural logarithmic values of the signal/noise ratio also showed no association between NRG1 variants and SPEM abnormality among patients with schizophrenia (P > 0.05). Despite the need for further replications in other cohorts, our findings provide additional supporting information that four variants in NRG1 investigated in this study may not be associated with schizophrenia and its related SPEM function in a Korean population.