Activating mutations of the KATP channel genes (either potassium inwardly-rectifying channel, subfamily J, member 11 (KCNJ11), or ATP-binding cassette transporter subfamily C member 8 (ABCC8)) or insulin gene (INS) are the most common causes of permanent neonatal diabetes mellitus (PNDM), whilst KCNJ11 and ABCC8 mutations have been shown to account for a minority of cases of TNDM [35, 40, 42, 43]. This evidence concerns the gene ABCC8 and transient neonatal diabetes mellitus.