diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php b/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
index c942621f6..eb50d1251 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php
@@ -752,6 +752,10 @@ class ClassMetadataInfo implements ClassMetadata
             $serialized[] = 'isReadOnly';
         }
 
+        if ($this->customGeneratorDefinition) {
+            $serialized[] = "customGeneratorDefinition";
+        }
+
         return $serialized;
     }