MYSM1 and lymphopenia: Several studies have found that MYSM1 deficiency or mutation can lead to defects during the development and function of HSCs, B cells, natural killer (NK) cells and dendritic cells, and it also results in the development of lymphopenia, anemia, and thrombocytopenia, and low B-cell and NK-cell counts in both mice and humans [45,51,52,53,54,55].