diff --git a/google/cloud/firestore_v1/field_path.py b/google/cloud/firestore_v1/field_path.py
index c3383cbb8..048eb64d0 100644
--- a/google/cloud/firestore_v1/field_path.py
+++ b/google/cloud/firestore_v1/field_path.py
@@ -31,7 +31,7 @@
 _ESCAPED_BACKTICK = _BACKSLASH + _BACKTICK
 
 _SIMPLE_FIELD_NAME = re.compile("^[_a-zA-Z][_a-zA-Z0-9]*$")
-_LEADING_ALPHA_INVALID = re.compile("^[_a-zA-Z][_a-zA-Z0-9]*[^_a-zA-Z0-9]")
+_LEADING_ALPHA_INVALID = re.compile(r"^[_a-zA-Z][_a-zA-Z0-9]*[~*/\[\]]")
 PATH_ELEMENT_TOKENS = [
     ("SIMPLE", r"[_a-zA-Z][_a-zA-Z0-9]*"),  # unquoted elements
     ("QUOTED", r"`(?:\\`|[^`])*?`"),  # quoted elements, unquoted
@@ -311,9 +311,7 @@ def from_string(cls, path_string: str):
                     raise ValueError("Empty element")
                 if _LEADING_ALPHA_INVALID.match(element):
                     raise ValueError(
-                        "Non-alphanum char in element with leading alpha: {}".format(
-                            element
-                        )
+                        "Invalid char in element with leading alpha: {}".format(element)
                     )
             return FieldPath(*elements)
 
diff --git a/tests/system/test_system.py b/tests/system/test_system.py
index b8adebb6b..d82d5113f 100644
--- a/tests/system/test_system.py
+++ b/tests/system/test_system.py
@@ -3151,6 +3151,28 @@ def in_transaction(transaction):
         assert inner_fn_ran is True
 
 
+@pytest.mark.parametrize("database", [None, FIRESTORE_OTHER_DB], indirect=True)
+def test_transaction_w_uuid(client, cleanup, database):
+    """
+    https://github.com/googleapis/python-firestore/issues/1012
+    """
+    collection_id = "uuid_collection" + UNIQUE_RESOURCE_ID
+    doc_ref = client.document(collection_id, "doc")
+    cleanup(doc_ref.delete)
+    key = "b7992822-eacb-40be-8af6-559b9e2fb0b7"
+    doc_ref.create({key: "I'm a UUID!"})
+
+    @firestore.transactional
+    def update_doc(tx, doc_ref, key, value):
+        tx.update(doc_ref, {key: value})
+
+    expected = "UPDATED VALUE"
+    update_doc(client.transaction(), doc_ref, key, expected)
+    # read updated doc
+    snapshot = doc_ref.get()
+    assert snapshot.to_dict()[key] == expected
+
+
 @pytest.mark.skipif(
     FIRESTORE_EMULATOR, reason="Query profile not supported in emulator."
 )
@@ -3206,6 +3228,24 @@ def in_transaction(transaction):
         assert inner_fn_ran is True
 
 
+@pytest.mark.parametrize("database", [None, FIRESTORE_OTHER_DB], indirect=True)
+def test_update_w_uuid(client, cleanup, database):
+    """
+    https://github.com/googleapis/python-firestore/issues/1012
+    """
+    collection_id = "uuid_collection" + UNIQUE_RESOURCE_ID
+    doc_ref = client.document(collection_id, "doc")
+    cleanup(doc_ref.delete)
+    key = "b7992822-eacb-40be-8af6-559b9e2fb0b7"
+    doc_ref.create({key: "I'm a UUID!"})
+
+    expected = "UPDATED VALUE"
+    doc_ref.update({key: expected})
+    # read updated doc
+    snapshot = doc_ref.get()
+    assert snapshot.to_dict()[key] == expected
+
+
 @pytest.mark.parametrize("with_rollback,expected", [(True, 2), (False, 3)])
 @pytest.mark.parametrize("database", [None, FIRESTORE_OTHER_DB], indirect=True)
 def test_transaction_rollback(client, cleanup, database, with_rollback, expected):