C1QTNF4 and systemic lupus erythematosus: Interestingly, there are reports of a gain-of-function mutation in the C1qtnf4 gene that correlates with early-onset, severe SLE in human patients [54,55], further supporting a role for the C1qtnf4 gene in autoimmune homeostasis and aberrant activity in SLE, as suggested by our findings.