For example, several immunodeficient rabbit lines have been produced by knocking out of genes such as Il2rg, Foxn1, and Rag2 (Song et al., 2013, 2017; Yan et al., 2014; Hashikawa et al., 2020); these animals are expected to make valuable contributions to regenerative medicine, cancer and primary immunodeficiency, as comprehensively reviewed elsewhere (Song et al., 2020). Here, RAG2 is linked to inborn error of immunity.