['Insulin resistance and hyperglycaemia are common in severe sepsis. Mitochondrial uncoupling protein 2 (UCP2) plays a role in insulin release and sensitivity.', 'To determine if a common, functional polymorphism in the UCP2 gene promoter region (the -866 G/A polymorphism) contributes to the risk of hyperglycaemia in severe sepsis.', 'In the prospective group 120 non-diabetic patients who were carriers of the G allele had significantly higher maximum blood glucose recordings than non-carriers (mean (SD) AA 8.5 (2.2) mmol/l; GA 8.5 (2.4) mmol/l; GG 10.1 (3.1) mmol/l; p = 0.0042) and required significantly more insulin to maintain target blood glucose (p = 0.0007). In the retrospective study 103 non-diabetic patients showed a similar relationship between maximum glucose and UCP genotype (AA 6.8 (2.3) mmol/l; GA 7.8 (2.2) mmol/l; GG 9.2 (2.9) mmol/l; p = 0.0078).'] Does a common UCP2 polymorphism predispose to stress hyperglycaemia in severe sepsis?