The following genes with an identifier have been found but that do not have a mapping to Ensembl: 3
http://classic.wikipathways.org/instance/WP455_r117740 OR3A4 with datasource Entrez Gene
http://classic.wikipathways.org/instance/WP455_r117740 OR2N1P with datasource Entrez Gene
http://classic.wikipathways.org/instance/WP455_r117740 Q9UDD9 with datasource UniProtKB
More details at https://www.wikipathways.org/WikiPathwaysCurator/GeneTests/genesWithoutEnsemblMapping