Genetic mutations underlying epimutations have been reported very infrequently in other imprinting disorders, including Russell–Silver Syndrome, transient neonatal diabetes mellitus and Beckwith–Wiedemann syndrome associated with KCNQ1OT1 (imprinting control region 2) hypomethylation. Here, KCNQ1OT1 is linked to transient neonatal diabetes mellitus.