HELLS and ICF syndrome: Our data suggest that CDCA7 functionally overlaps in the regulation of clustered Pcdh gene expression with at least two other ICF syndrome–causing factors, the de novo DNA methyltransferase DNMT3B and the chromatin remodeler HELLS, such that their disruption leads to aberrant hypomethylation and increased expression of Pcdh isoforms in neuronal tissue (35) or mouse embryonic fibroblasts (MEFs) (63), respectively.