C4A and systemic lupus erythematosus: In the past two decades, several CNVs associated with SLE development have been identified, such as C4 (C4A, C4B) (Yang et al., 2007; Pereira et al., 2019; Kamitaki et al., 2020; Lundtoft et al., 2022), FCGR3A, FCGR3B (Willcocks et al., 2008; Niederer et al., 2010), CCL3L1 (Gonzalez et al., 2005), RABGAP1L (Kim et al., 2013), TLR7 (Garcia-Ortiz et al., 2010) and HSP90 (Zhang et al., 2019).