MAPT and Alzheimer disease: Similarly, CSF GAP-43 had significant positive correlations with P-tau in CN ε4−, CN ε4+, MCI ε4−, MCI ε4+, and AD ε4+ groups (rs = 0.579, p < 0.001; rs = 0.576, p < 0.001; rs = 0.581, p < 0.001; rs = 0.611, p < 0.001; rs = 0.509, p < 0.001; respectively), except for AD ε4− group (rs = 0.227, p = 0.158) (Table 2 and Figure 2C).