The following genes with an identifier have been found but that do not have a mapping to Ensembl: 3
http://classic.wikipathways.org/instance/WP921_r117410 APOC3 with datasource Entrez Gene
http://classic.wikipathways.org/instance/WP921_r117410 APOA1 with datasource Entrez Gene
http://classic.wikipathways.org/instance/WP921_r117410 APOC2 with datasource Entrez Gene
More details at https://www.wikipathways.org/WikiPathwaysCurator/GeneTests/genesWithoutEnsemblMapping