Two other novel candidate AD risk genes that we nominated in this study, AP4E1 and AP4M1, encode two of the four subunits of the heterotetrameric adaptor protein complex 4 (AP-4), which is required for the sorting of transmembrane proteins like APP from the trans-Golgi network (TGN) to endosomes58. The gene discussed is AP4M1; the disease is Alzheimer disease.