GCK and diabetes mellitus: As detailed in Table 1 and Table S1, three patients (2.5%) had variants in HADH gene, 2 (1.7%) in GCK. Additionally, two previously reported HNF4A variants, p.R63W and p.V382I, associated with maturity-onset diabetes of the young (MODY) [31, 32], were found in two patients (1.7%) without family history of hyperinsulinism and/or diabetes.