Of interest here, pathogenic variants associated with MGS have been identified in the genes encoding subunits of the origin recognition complex ORC1, ORC4, and ORC6 (21); components of the CMG complex MCM3 (22), MCM5 (23), MCM7 (22), CDC45 (24–27), and GINS2 (28); factors involved in the assembly of the CMG complex CDT1, CDC6 (21),and GMNN (29); and DONSON, a protein that promotes replication fork stability (30). Here, MCM3 is linked to Mungan syndrome.