diff --git a/runtype/base_types.py b/runtype/base_types.py
index 902d88f..2c00310 100644
--- a/runtype/base_types.py
+++ b/runtype/base_types.py
@@ -208,7 +208,7 @@ def __eq__(self, other):
 
 
     def __le__(self, other):
-        if isinstance(other, type(self)):
+        if isinstance(other, GenericType):
             return self.base <= other.base and self.item <= other.item
 
         elif isinstance(other, DataType):
diff --git a/tests/test_basic.py b/tests/test_basic.py
index b93f1ff..9b91229 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -144,6 +144,9 @@ def test_tuple_ellipsis(self):
         assert_isa((1,2,3), Tuple[int, ...])
         self.assertRaises(TypeError, assert_isa, (1, "2"), Tuple[int, ...])
 
+        assert issubclass(Tuple[str, ...], typing.Sequence[str])
+        assert not issubclass(Tuple[str, ...], typing.Sequence[int])
+
     @unittest.skipIf(sys.version_info < (3, 8), "Not supported before Python 3.8")
     def test_py38(self):
         assert isa('a', typing.Literal['a', 'b'])