For example, in NOD mouse, a model of spontaneous type 1 diabetes (T1D), a R619W mutation in the protein tyrosine phosphatase non-receptor type 22 (Ptpn22) gene was introduced by CRISPR/Cas9 and homology-directed repair (Lin et al. 2016). The gene discussed is PTPN22; the disease is type 1 diabetes mellitus.