Lack of association between sigma receptor gene variants and schizophrenia

Several pharmacological studies suggest the possible involvement of sigma(1) receptors in the pathogenesis of schizophrenia. An association has been reported between schizophrenia and two variants (GC-241-240TT and Gln2Pro) in the sigma(1) receptor gene (SIGMAR1). We also previously reported that, along with T-485 A, these two variants alter SIGMAR1 function. To investigate the role of SIGMAR1 in conveying susceptibility to schizophrenia, we performed a case-control study. We initially screened for polymorphisms in the SIGMAR1 coding region using PCR-single strand conformation polymorphism analysis. The distribution of SIGMAR1 polymorphisms was analyzed in 100 schizophrenic and 104 control subjects. A novel G620A variant was detected in exon4. G620A was predicted to alter the amino acid represented by codon 211 from arginine to glutamine. Our case-control study showed no significant association between the T-485 A, GC-241-240TT, Gln2Pro, and G620A (Arg211Gln) variants and schizophrenia and clinical characteristics. These findings suggest that these SIGMAR1 variants may not affect susceptibility to schizophrenia.