To date, around 26 different ACP5 variants have been identified in patients with SPENCD from various ethnic groups (Lausch et al. 2011; Girschick et al. 2015; Briggs et al. 2016; Bilginer et al. 2016; Sacri et al. 2017; Zhong et al. 2018; Kara et al. 2020). This evidence concerns the gene ACP5 and Spondyloenchondrodysplasia with immune dysregulation.