diff --git a/typet/__init__.py b/typet/__init__.py
index 238cac4..65bd085 100644
--- a/typet/__init__.py
+++ b/typet/__init__.py
@@ -639,7 +639,8 @@ def __new__(cls, name, bases, attrs):
                           names, attrs, annotations, attr)]
             typed_attrs['_tp__typed_properties'] = properties
             typed_attrs['_tp__undefined_typed_properties'] = [
-                attr for attr in properties if attr not in attrs]
+                attr for attr in properties if attr not in attrs or
+                attrs[attr] is None and use_comment_type_hints]
             return super(_AnnotatedObjectMeta, cls).__new__(
                 cls, name, bases, typed_attrs)