diff --git a/src/db_utils/fill_splicing_lore_tables.py b/src/db_utils/fill_splicing_lore_tables.py
index 63cadbb06d90a534c7f390504ee95b5688b3c121..1027dc0087c424bacd940b1991356bccef8fc7d4 100644
--- a/src/db_utils/fill_splicing_lore_tables.py
+++ b/src/db_utils/fill_splicing_lore_tables.py
@@ -33,7 +33,7 @@ def load_ase_event() -> pd.DataFrame:
     :return: The dataframe of splicing lore alternative splicing events
     """
     logging.debug('loading cin_project_splicing_lore')
-    df = pd.read_csv(Config.ase_event_file, sep="\t")
+    df = pd.read_csv(Config.ase_event_file, sep="\t", dtype={"chromosome": 'object'})
     df.drop(["gene_symbol", "chromosome", "start", "stop", "exons_flanquants"],
             inplace=True, axis=1)
     cols = list(df.columns)