PTPRD and Alzheimer disease: By analyzing the results, we identified the intersection genes in the EMCI-HC group, LMCI-HC group and AD-HC group, including CSMD1, CDH13, PTPRD, MACROD2 and WWOX. We also identified some significant pathways associated with AD, such as the calcium signaling pathway (corrected p-value = 9.83 × 106 in EMCI-HC), arrhythmogenic right ventricular cardiomyopathy (corrected p-value = 4.75 × 105 in EMCI-HC and glutamatergic synapse pathway (corrected p-value = 1.37 × 104 in EMCI-HC).