In 2005 for the first time there were reported two patients with MLID presented transient neonatal diabetes mellitus (TNDM) and hypomethylation of both iDMRs of KCNQ1OT1 gene (Arima et al., 2005) and of PLAGL1, an antiapoptotic (Shuman et al., 2006) gene located at chromosome 6q24 (Bliek et al., 2009b). The gene discussed is PLAGL1; the disease is transient neonatal diabetes mellitus.