FAM111B and Rothmund-Thomson syndrome: The identification of mutations in FAM111B provided definitive evidence for POIKTMP and distinguishes it from other types of hereditary poikiloderma, such as Rothmund-Thomson syndrome (RTS), hereditary sclerosing poikiloderma of Weary, Kindler syndrome and Clericuzio-type poikiloderma with neutropaenia (Arnold et al., 2010; Küry et al., 2016; Gatinois et al., 2020).