Functional Overlap of Inborn Errors of Immunity and Metabolism Genes Define T Cell Immunometabolic Vulnerabilities

SUMMARYInborn Errors of Metabolism (IEM) and Immunity (IEI) are Mendelian diseases in which complex phenotypes and patient rarity can limit clinical annotations. Few genes are assigned to both IEM and IEI, but immunometabolic demands suggest functional overlap is underestimated. We applied CRISPR screens to test IEM genes for immunologic roles and IEI genes for metabolic effects and found considerable crossover. Analysis of IEM showed N-linked glycosylation and thede novohexosamine synthesis enzyme,Gfpt1, are critical for T cell expansion and function. Interestingly,Gfpt1-deficient TH1 cells were more affected than TH17 cells, which had increasedNagkfor salvage UDP-GlcNAc synthesis. Screening IEI genes showed the transcription factorBcl11bpromotes CD4+T cell mitochondrial activity andMcl1expression necessary to prevent metabolic stress. These data illustrate a high degree of functional overlap of IEM and IEI genes and point to potential immunometabolic mechanisms for a previously unappreciated set of these disorders.HIGHLIGHTSInborn errors of immunity and metabolism have greater overlap than previously knownGfpt1deficiency causes an IEM but also selectively regulates T cell subset fateLoss ofBcl11bcauses a T cell deficiency IEI but also harms mitochondrial functionMany IEM may have immune defects and IEI may be driven by metabolic mechanisms