ST8SIA2 and schizophrenia: As the structural and functional analyses of polySia [1,27,30,31,32,33] have been established, the precise evaluations of these mutations and single nucleotide polymorphism (SNP)s of ST8SIA2 that have been reported to have some relationship with schizophrenia and bipolar disorder could be performed [1,26,27,33,34].