The following genes with an identifier have been found but that do not have a mapping to Ensembl: 3
http://classic.wikipathways.org/instance/WP5276_r134703 CYP1A1 with datasource UniProtKB
http://classic.wikipathways.org/instance/WP5276_r134703 STS with datasource UniProtKB
http://classic.wikipathways.org/instance/WP5276_r134703 HSD17B12 with datasource UniProtKB
More details at https://www.wikipathways.org/WikiPathwaysCurator/GeneTests/genesWithoutEnsemblMapping