diff --git a/nomad/graph/graph_reader.py b/nomad/graph/graph_reader.py
index 4807f50860b5e9ef240cd28459fa464cfd1efad8..eae2bd8aed531a0fe4476e16ff8a1be50fc3e28b 100644
--- a/nomad/graph/graph_reader.py
+++ b/nomad/graph/graph_reader.py
@@ -2967,6 +2967,7 @@ class DefinitionReader(GeneralReader):
             return
 
         for name, unwrap in (
+            ('extending_sections', False),
             ('base_sections', False),
             ('sub_sections', True),
             ('quantities', False),