FBN1 and Alzheimer disease: The mean onset age for AD in individuals with FBN1 positive-variant (42.55 ± 6.95 years) was much lower than that of the non-FBN1 positive-variant group (49.63 ± 10.31 years, p = 0.03, Figure 2), whereas the mean onset age in the significant SNPs group showed no differences from that of other groups.