The WTCCC T2D cohort (n = 1,914) were all diagnosed between 25 and 75 years of age, were Glutamic Acid Decarboxylase (GAD) autoantibody negative and were either treated with diet/oral hypoglycaemic agents or had an interval of at least 1 year between diagnosis and the institution of insulin therapy. The gene discussed is INS; the disease is type 2 diabetes mellitus.