Therefore, the DNA hypomethylation and chromosomal abnormalities in mice with Dnmt3b mutations or derived cell cultures is more extensive (including centromeric as well as juxtacentromeric DNA) than in the DNMT3B-mutant ICF syndrome in humans, even when comparing the same DNMT3B mutations, and the nature of the immune dysfunction is different. This evidence concerns the gene DNMT3B and immune system disorder.