We performed a conditional analysis on 16p11.2 genes whose top phenome associations included psychosis: NPIPB11, BOLA2, MAPK3, SEPT1, SLX1B, TBC1D10B. By comparing whether the p value of association stayed constant vs. increased after conditioning, we found that NPIPB11, SEPT1, SLX1B, and TBC1D10B were likely independent associations, whereas BOLA2 and MAPK3 may be associated with psychosis at least partly by correlation with the other four. The gene discussed is SEPTIN1; the disease is psychotic disorder.