diff --git a/lib/index.js b/lib/index.js
index 1dc3c33..bb91c74 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -23,7 +23,7 @@ function copyIfMessageKey(target, key, value) {
 }
 // are the required keys of a valid Message present?
 function isValidMessage(obj) {
-    return "id" in obj && "defaultMessage" in obj;
+    return "id" in obj;
 }
 function extractMessagesForDefineMessages(objLiteral) {
     var messages = [];