FLG and Alzheimer disease: FLG mutations are one of the most robust genetic risk factors for AD,15, 40 but a number of factors can mediate this relationship, including race and age.34 The heterogeneous patterns of associations with FLG mutations in our study populations, which are ethnically homogeneous and were assessed at the same age, indicate that different case–control definitions may have an adverse impact on our understanding of the underlying pathophysiological mechanisms.