Hypermethylation of the H19/IGF2 ICR can be found in some patients with Beckwith-Wiedemann syndrome (BWS) and focal congenital hyperinsulinaemia (FoCHI); the latter is a glucose metabolism disease characterized by abnormal insulin secretion by pancreatic β cells and hypoglycaemia (Ohlsson et al., 1993). The gene discussed is INS; the disease is Beckwith-Wiedemann syndrome.