Systematic mutation analysis of the human glutamate receptor, ionotropic, N-methyl-D-aspartate 1 gene (GRIN1) in schizophrenic patients

Schizophrenia is a severe, complex mental disorder with unknown etiology. Abnormal glutamate neurotransmission has been proposed as one of the hypotheses of the pathogenesis of schizophrenia. Mohn et al. recently reported that transgenic mice with the reduced glutamate receptor, ionotropic, N-methyl-D-aspartate 1 gene (GRIN1) (formerly referred to as NMDAR1) expression display schizophrenia-like behaviors, which can be ameliorated by antipsychotic drug treatment. Their report promoted us to examine whether mutations in the human GRIN1 gene may convey genetic susceptibility to schizophrenia. To test this possibility, we systematically screened mutations in the promoter region and in all the exons of the human GRIN1 gene in a cohort of Chinese schizophrenic patients from Taiwan. Using single-strand conformation polymorphism analysis and autosequencing, we identified two single nucleotide polymorphisms, designated g.-1140G > A and g.-855G > C, respectively, at the 5′-untranslated region of the human GRIN1 gene. Genetic association study, however, revealed no association of these two single nucleotide polymorphisms with schizophrenia in our patients. Besides, no other mutations of the human GRIN1 gene were detected in this study. Our data suggest that the human GRIN1 gene may not contribute substantially to the genetic etiology of schizophrenia in our population.