The following DataNodes have no identifier: 2
http://classic.wikipathways.org/instance/WP1148_r117469 http://rdf.wikipathways.org/Pathway/WP1148_r117469/DataNode/f28 (HES1)
http://classic.wikipathways.org/instance/WP1148_r117469 http://rdf.wikipathways.org/Pathway/WP1148_r117469/DataNode/c78 (PTCRA)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier