Quantification of claudin-5 expression in blood vessels revealed that, while there were no significant differences between the diagnosis groups in the absence of the rs10314 variant, claudin-5 levels were significantly lower in individuals with a diagnosis of schizophrenia who had the rs10314 variant compared to control subjects who harboured the rs10314 variant (*P<0.05, Figure 5g). Here, CLDN5 is linked to schizophrenia.