A fifth significant locus, KCNIP4, Potassium Voltage-Gated Channel Interacting Protein 4, relates to response to intracellular calcium, and interacts with presenilin. Calcium signaling is important in an extensive range of behavioral traits.18,24 A sixth locus, CAMKV (CaM Kinase Like Vesicle Associated), was associated with educational attainment in the UK Biobank sample25. The other two GWS associations are at LINC01360 and SRPK2, both less well understood in terms of their function. One gene significantly associated with REX in the gene-based analysis, RAB27B, has been implicated in exosome production necessary for appropriate responsiveness to inflammatory stimuli.26 Given recent hypotheses about immune dysfunction in PTSD,3,27 the involvement of this locus deserves further scrutiny.
