<b><i>VRK2</i></b>, a Candidate Gene for Psychiatric and Neurological Disorders

Recent large-scale genetic approaches, such as genome-wide association studies, have identified multiple genetic variations that contribute to the risk of mental illnesses, among which single nucleotide polymorphisms (SNPs) within or near the vaccinia related kinase 2 (<i>VRK2</i>) gene have gained consistent support for their correlations with multiple psychiatric and neurological disorders including schizophrenia (SCZ), major depressive disorder (MDD), and genetic generalized epilepsy. For instance, the genetic variant rs1518395 in <i>VRK2</i> showed genome-wide significant associations with SCZ (35,476 cases and 46,839 controls, <i>p</i> = 3.43 × 10^–8) and MDD (130,620 cases and 347,620 controls, <i>p</i> = 4.32 × 10^–12) in European populations. This SNP was also genome-wide significantly associated with SCZ in Han Chinese population (12,083 cases and 24,097 controls, <i>p</i> = 3.78 × 10^–13), and all associations were in the same direction of allelic effects. These studies highlight the potential roles of <i>VRK2</i> in the central nervous system, and this gene therefore might be a good candidate to investigate the shared genetic and molecular basis between SCZ and MDD, as it is one of the few genes known to show genome-wide significant associations with both illnesses. Furthermore, the <i>VRK2</i> gene was found to be involved in multiple other congenital deficits related to the malfunction of neurodevelopment, adding further support for the involvement of this gene in the pathogenesis of these neurological and psychiatric illnesses. While the precise function of <i>VRK2</i> in these conditions remains unclear, preliminary evidence suggests that it may affect neuronal proliferation and migration via interacting with multiple essential signaling pathways involving other susceptibility genes/proteins for psychiatric disorders. Here, we have reviewed the recent progress of genetic and molecular studies of <i>VRK2</i>, with an emphasis on its role in psychiatric illnesses and neurological functions. We believe that attention to this important gene is necessary, and further investigations of <i>VRK2</i> may provide hints into the underlying mechanisms of SCZ and MDD.