2000; Suchi et al. 2003; Stanley et al. 2004) in ABCC8 were identified. These mutations are in highly conserved regions. There is still controversy regarding the association between the p.E1506K mutation and diabetes type II (Pinney, et al., 2008; Vieira et al. 2010). The history of the families of our proband carrying the p.E1506K mutation does not agree with the theory that this mutation predisposes one to early‐onset type II diabetes. Patient 10 was compound heterozygous for the c.1279‐4A>G mutation in GLUD1, and her blood ammonia level was 147 μmol/L (normal range: 11–35 μmol/L). Here, GLUD1 is linked to Onset.