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The complement C4 genetic diversity in first episode psychosis of the OPTiMiSE cohort

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Christina Mariaselvam, Ching-Lien Wu, Wahid Boukouaci, Jean-Romain Richard, Caroline Barau, Philippe Le Corvoisier, Paola Dazzan, Alice Egerton, Thomas Pollak, Philip McGuire, D Rujescu, Stephane Jamain, Marion Leboyer, Ryad Tamouza

Original languageEnglish
JournalSchizophrenia Bulletin Open
Published17 Feb 2021

King's Authors


Recent findings implicate the complement C4 gene in gray matter loss in schizophrenia. In a large cohort of patients with first episode psychosis (FEP) we aimed to i) characterize the frequency of C4 gene copy number variations (CNVs) and HERV-K Ins/Del events as compared to that in healthy controls (HC), ii) evaluate whether C4 gene structural variants influence baseline clinical symptoms and treatment response to amisulpride. We genotyped 271 FEP subjects and 221 HC for C4 CNV and HERV-Ins/Del (C4A & C4B isoforms; C4-HERV structural forms (C4AL; C4AS; C4BL; C4BS) variations using droplet digital PCR. Overall, the gene frequencies of both C4 isoforms and C4-HERV structural forms did not significantly differ between groups. At genotype level, we found that the C4 AL-AL-BL-BL genotype (AL-BL haplotype) was significantly more frequent in FEP as compared to HC. Apart from a marginal observation concerning the C4 AL-AL-BL-BL genotype (AL-BL haplotype), possibly reflecting a relationship with schizophrenia, we did not find any correlation between C4 genetic and clinical characteristics or treatment response in FEP.

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