diff --git a/src/pmotools/pmo_builder/panel_information_to_pmo.py b/src/pmotools/pmo_builder/panel_information_to_pmo.py
index 563307f..da14689 100644
--- a/src/pmotools/pmo_builder/panel_information_to_pmo.py
+++ b/src/pmotools/pmo_builder/panel_information_to_pmo.py
@@ -289,9 +289,11 @@ def build_target_info_dict(
             if self.gene_name_col:
                 target_dict["gene_name"] = row[self.gene_name_col]
             if self.target_attributes_col:
-                target_dict["target_attributes"] = row[
-                    self.target_attributes_col
-                ].split(self.target_attributes_col_delimiter)
+                target_attributes = row[self.target_attributes_col]
+                if pd.notna(target_attributes) and str(target_attributes).strip():
+                    target_dict["target_attributes"] = str(target_attributes).split(
+                        self.target_attributes_col_delimiter
+                    )
             if self.additional_target_info_cols:
                 for col in self.additional_target_info_cols:
                     value = row[col]