GRB10 and transient neonatal diabetes mellitus: Biallelic ZFP57 variants cause TNDM with MLID, with a characteristic DNA methylation signature of LOM of PLAGL1, GRB10 and PEG3. Current ISPAD (International Society for Pediatric and Adolescent Diabetes) clinical practice consensus guidelines recommend ZFP57 sequencing in individuals with TNDM when hypomethylation of PLAGL1 is detected, without requiring MLID testing to confirm the distinctive DNA methylation signature [97].