AIM: ATP-sensitive potassium channels are important regulators of insulin 
secretion. They consist of four sulphonylurea receptor (encoded by ABCC8) and 
four inwardly rectifying protein (encoded by KCNJ11) subunits. Activating ABCC8 
mutations lead to decreased insulin secretion and to diabetes. Wide phenotype 
variability is associated with single ABCC8 mutations, ranging from transient or 
permanent neonatal diabetes (ND) with or without developmental delay (DEND 
syndrome) to very mild phenotypes. This report describes the case of a Caucasian 
infant diagnosed with ND at the age of 2 months due to a novel ABCC8 missense 
mutation.
METHODS: ABCC8 was analyzed by sequence analysis. The mutation was present in 
the patient and her family and was found to be associated with phenotypes 
ranging from ND to asymptomatic impaired fasting glucose (IFG).
RESULTS: A novel His863Tyr ABCC8 mutation was identified in a 2-month-old girl 
diagnosed with ND. After an initial insulin treatment, treatment with 
glibenclamide was initiated and the treatment with insulin discontinued. The 
same mutation was found in her father, who had been fortuitously diagnosed with 
diabetes and had an HbA(1c) level of 9% (74.8 mmol/mol). The patient's brother 
and mother both had normal fasting glucose, and were not found to be carriers of 
the mutation. However, the same mutation was found in her grandmother, who had 
been asymptomatic and discovered IFG (6.9 mmol/L) with an HbA(1c) of 6.8% (50.8 
mmol/mol).
CONCLUSION: This case describes a novel ABCC8 mutation and offers a further 
illustration of the highly variable phenotypes associated with an identical 
mutation present across three generations.