No association between polymorphisms of DAO and DAOA genes and homicidal behaviors in Korean schizophrenia

Is the EFNB2 locus associated with schizophrenia? Single nucleotide polymorphisms and haplotypes analysis

Recently, evidence of linkage of schizophrenia to chromosome 13q22-q34 has been demonstrated in multiple studies. Based on structure and function, EFNB2 may be considered as a compelling candidate gene for schizophrenia on chromosome 13q33. We genotyped three single-nucleotide polymorphisms (SNPs: rs9520087, rs11069646, and rs8000078) in this region in 846 Han Chinese subjects (477 cases and 369 controls). Significant association between an allele of marker rs9520087 and schizophrenia was found. Furthermore, since no LD was observed in the three SNPs linkage disequilibrium estimation, all three SNPs were used in multiple SNPs haplotype analysis, and a strongly significant difference was found for the common haplotype TTC. Overall our findings indicate that EFNB2 gene may be a candidate susceptibility gene for schizophrenia in the Han Chinese population, and also provide further support for the potential importance of the NMDA receptor pathway in the etiology of schizophrenia.

Sex-different association of DAO with schizophrenia in Koreans

The gene encoding D-amino acid oxidase (DAO), which acts as a receptor for the schizophrenia-associated neurotransmitter, N-methyl-D-aspartate (NMDA), is regarded as a potential candidate gene for schizophrenia. However, the potential association of the DAO gene with schizophrenia has been the subject of some debate. Here, we tested three single nucleotide polymorphisms (SNPs) of DAO in a group of Korean schizophrenia patients, and found no significant association in the overall study subjects. Interestingly, however, we found gender-specific differences in allele distributions, with SNP rs2070586 appearing to act as a risk allele in female schizophrenia patients, but as a protective allele in males. Our data support the hypothesis that DAO plays a role in schizophrenia, possibly in a gender-dependent manner.

D-amino acid oxidase: physiological role and applications

D-Amino acids play a key role in regulation of many processes in living cells. FAD-dependent D-amino acid oxidase (DAAO) is one of the most important enzymes responsible for maintenance proper level of D-amino acids. The most interesting and important data for regulation of the nervous system, hormone secretion, and other processes by D-amino acids as well as development of different diseases under changed DAAO activity are presented. The mechanism of regulation is complex and multi-parametric because the same enzyme simultaneously influences the level of different D-amino acids, which can result in opposing effects. Use of DAAO for diagnostic and therapeutic purposes is also considered.