ACP5 and Spondyloenchondrodysplasia with immune dysregulation: Interestingly, since the description of causative ACP5 mutations [7, 8] the disorder has been designated under two separate Online Mendelian Inheritance in Man (OMIM) entries, namely SPENCD (271,550) and SPENCD with immune dysregulation (SPENCDI) (607,944).