diff --git a/src/metakb/database.py b/src/metakb/database.py
index 350ba172..aa42dafa 100644
--- a/src/metakb/database.py
+++ b/src/metakb/database.py
@@ -74,7 +74,7 @@ def _get_credentials(
 
 _CONSTRAINTS = {
     "coding_constraint": "CREATE CONSTRAINT coding_constraint IF NOT EXISTS FOR (c:Coding) REQUIRE (c.code, c.label, c.system) IS UNIQUE;",
-    "gene_id_constraint": "CREATE CONSTRAINT gene_id_constraint IF NOT EXISTS FOR (n:Gene}) REQUIRE n.id IS UNIQUE;",
+    "gene_id_constraint": "CREATE CONSTRAINT gene_id_constraint IF NOT EXISTS FOR (n:Gene) REQUIRE n.id IS UNIQUE;",
     "disease_id_constraint": "CREATE CONSTRAINT disease_id_constraint IF NOT EXISTS FOR (n:Disease) REQUIRE n.id IS UNIQUE;",
     "therapeuticprocedure_id_constraint": "CREATE CONSTRAINT therapeuticprocedure_id_constraint IF NOT EXISTS FOR (n:TherapeuticProcedure) REQUIRE n.id IS UNIQUE;",
     "variation_id_constraint": "CREATE CONSTRAINT variation_id_constraint IF NOT EXISTS FOR (n:Variation) REQUIRE n.id IS UNIQUE;",