INS and congenital isolated hyperinsulinism: Individuals with KATP channel mutations (n=761) had higher birthweights (mean 4333g vs 3512g, P=6 x 10-94, mean difference 821g, 95% CI 748g-894g), were more likely to be diagnosed in the first week of life (85% vs 72%, P=1 x 10-9), had a higher insulin level at diagnosis (mean 162.2pmol/l vs 115.4pmol/l, P=1 x 10-8) and were less likely to respond to diazoxide, the mainstay treatment for CHI (32% vs 88%, P=2 x 10-84) compared to individuals with CHI of unknown genetic aetiology (n=862) (Table 1).