diff --git a/src/genomic_features/ensembl/ensembldb.py b/src/genomic_features/ensembl/ensembldb.py
index 82f420d..3d61ac7 100644
--- a/src/genomic_features/ensembl/ensembldb.py
+++ b/src/genomic_features/ensembl/ensembldb.py
@@ -309,7 +309,12 @@ def _build_query(
         else:
             query = self.db.table(table)
         # add filter
-        query = query.filter(filter.convert()).select(cols).order_by(cols)
+        
+        filter = filter.convert()
+        if filter is not None:
+            query = query.filter(filter)
+            
+        query = query.select(cols).order_by(cols)
         return query
 
     def _join_query(