Moreover, abnormal peripherals levels of complement proteins such as C4, C1, C1q, C2, C3, C4 and the terminal complement complex (TCC) have been reported in patients with schizophrenia or first episode psychosis (Kopczynska et al., 2017; Nimgaonkar et al., 2017; Sekar et al., 2016). Here, C4A is linked to schizophrenia.