One of them involves the HIST1H2BH gene, which currently is not associated with any of the OMIM-codified disorders, the other one involves the HIST1H1E gene whose de novo frameshift variants at the C-terminal tail associate with an ID syndrome, the Rahman Syndrome (#617537), characterized by a peculiar pattern of growth, specific facial features, premature aging and a specific hypomethylation profile (Ciolfi 2020). This evidence concerns the gene H2BC9 and Rahman syndrome.