Among the 137 immunodeficient patients with iVDPV infection in the WHO Registry for whom the type of PID was known, 45 patients (33%) had SCID, 23 (17%) had agammaglobulinemia, 22 (16%) had CVID, and 19 (14%) had MHC class II deficiency (Table 2). The gene discussed is HLA-C; the disease is agammaglobulinemia.