diff --git a/src/hdmf_zarr/backend.py b/src/hdmf_zarr/backend.py
index 5172191f..9535b0c8 100644
--- a/src/hdmf_zarr/backend.py
+++ b/src/hdmf_zarr/backend.py
@@ -1173,6 +1173,7 @@ def __read_dataset(self, zarr_obj, name):
                     break
             retrieved_dtypes = [dtype_dict['dtype'] for dtype_dict in dtype]
             if has_reference:
+                # TODO:  BuilderZarrTableDataset does not yet support region reference
                 data = BuilderZarrTableDataset(zarr_obj, self, retrieved_dtypes)
         elif self.__is_ref(dtype):
             # reference array