APOBEC3D and viral infectious disease: APOBEC3s (A3s) gene cluster is located on chromosome 22q13.1-q13.2 including APOBEC3A, APOBEC3B, APOBEC3C, APOBEC3D, APOBE-C3E, APOBEC3F, APOBEC3G, and APOBEC3H which are arranged in tandem and play key roles in intracellular defense against viral infection (15, 16).