The following genes with an identifier have been found but that do not have a mapping to Ensembl: 3
http://classic.wikipathways.org/instance/WP854_r117389 GGT1 with datasource Entrez Gene
http://classic.wikipathways.org/instance/WP854_r117389 PTGES2 with datasource Entrez Gene
http://classic.wikipathways.org/instance/WP854_r117389 PTGDS with datasource Entrez Gene
More details at https://www.wikipathways.org/WikiPathwaysCurator/GeneTests/genesWithoutEnsemblMapping