diff --git a/src/hb-common.cc b/src/hb-common.cc
index a67fcf85e..ca2b32784 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -545,6 +545,7 @@ hb_script_get_horizontal_direction (hb_script_t script)
 
     /* https://github.com/harfbuzz/harfbuzz/issues/1000 */
     case HB_SCRIPT_OLD_ITALIC:
+    case HB_SCRIPT_RUNIC:
 
       return HB_DIRECTION_INVALID;
   }