diff --git a/scripts/run/clustering.py b/scripts/run/clustering.py
index ba0e63e..7edc236 100644
--- a/scripts/run/clustering.py
+++ b/scripts/run/clustering.py
@@ -604,8 +604,9 @@ def run_clustering(input_path,
             init_mutabilities_module(mutab_config)
             seq_df = seq_df[seq_df["Reference_info"] == 1]   
             seq_df['Exons_coord'] = seq_df['Exons_coord'].apply(eval)  
-            genes_to_process = [gene for gene in genes_to_process if gene in seq_df["Gene"].unique()]
-            genes_not_mutability = [gene for gene in genes_to_process if gene not in seq_df["Gene"].unique()]
+            genes_in_seq_df = set(seq_df["Gene"].unique())
+            genes_not_mutability = [gene for gene in genes_to_process if gene not in genes_in_seq_df]
+            genes_to_process = [gene for gene in genes_to_process if gene in genes_in_seq_df]
             logger.debug("Computing probabilities..")
             miss_prob_dict = get_miss_mut_prob_dict(mut_rate_dict=None, seq_df=seq_df,
                                                     mutability=True, mutability_config=mutab_config)
@@ -615,7 +616,7 @@ def run_clustering(input_path,
                 result_gene = pd.DataFrame({"Gene" : genes_not_mutability,
                                             "Uniprot_ID" : np.nan,
                                             "F" : np.nan,
-                                            "Mut_in_gene" : np.nan,
+                                            "Mut_in_gene" : genes.loc[genes_not_mutability].values,
                                             "Ratio_not_in_structure" : np.nan,
                                             "Ratio_WT_mismatch" : np.nan,
                                             "Mut_zero_mut_prob" : np.nan,