The most frequent main genetic causes of combined immunodeficiencies with associated or syndromic features in children infected with SARS-CoV-2 were large (3 Mb) deletion of 22q11.2 (n = 40) [46, 56, 63, 65, 81, 92, 95, 97, 108], ATM deficiency (n = 24) [34, 46, 48, 52, 62–64, 73, 74, 81, 97, 108, 117, 118, 124], Wiskott-Aldrich syndrome protein deficiency (n = 14) [5, 40, 46, 48, 63, 65, 81, 95, 99, 124], NBS1 (n = 9) [81, 108], DNMT3B (n = 5) [19, 48, 73], ARPC1B (n = 3) [39, 40, 95], STIM1 (n = 2) [34, 74], IKBKG (n = 2) [30, 73], and PGM3 (n = 2) [76, 95]. The gene discussed is DNMT3B; the disease is immune system disorder.