diff --git a/include/causali.h b/include/causali.h
index 1a440ca34..a78742ef1 100755
--- a/include/causali.h
+++ b/include/causali.h
@@ -23,6 +23,7 @@
 #define CAU_SOSPESO    "SOSPESO"
 #define CAU_VALINTRA   "VALINTRA"
 #define CAU_SOLOIVA    "SOLOIVA"
+#define CAU_LIQDIFF    "LIQDIFF"
 #define CAU_MOVIND     "MOVIND"
 #define CAU_PROVV      "PROVV"
 #define CAU_CODCAUREG  "CODCAUREG"