GFAP and Alzheimer disease: This analysis revealed that as the synaptophysin: GFAP ratio increased, the percentage of HMGCRΔ13 increased (Figure 5); linear regression analysis found that the percentage of HMGCRΔ13 was significantly associated with the synaptophysin: GFAP ratio (p = 0.026) while rs3846662 and AD were not significant (p > 0.05).