Given that atypical diabetes presentations are common in black Africans, the older peak age of onset of diabetes and the reduction of the positivity rate of GAD65 autoantibody may suggest non-autoimmune diabetes in these younger black adults – a finding that has been recently demonstrated in older adults diagnosed with T1D in Europe, where a reduction in islet antibody prevalence with older age in clinically diagnosed T1D appears to reflect misclassification (74, 75). Here, GAD2 is linked to type 1 diabetes mellitus.