diff --git a/src/cool_seq_tool/mappers/exon_genomic_coords.py b/src/cool_seq_tool/mappers/exon_genomic_coords.py
index 6b55746..89974ef 100644
--- a/src/cool_seq_tool/mappers/exon_genomic_coords.py
+++ b/src/cool_seq_tool/mappers/exon_genomic_coords.py
@@ -14,7 +14,7 @@
     Strand,
 )
 from cool_seq_tool.sources.mane_transcript_mappings import ManeTranscriptMappings
-from cool_seq_tool.sources.uta_database import UtaDatabase
+from cool_seq_tool.sources.uta_database import GenomicAlnData, UtaDatabase
 from cool_seq_tool.utils import service_meta
 
 _logger = logging.getLogger(__name__)
@@ -653,7 +653,7 @@ async def _get_alt_ac_start_and_end(
         tx_exon_start: _ExonCoord | None = None,
         tx_exon_end: _ExonCoord | None = None,
         gene: str | None = None,
-    ) -> tuple[tuple[tuple[int, int], tuple[int, int]] | None, str | None]:
+    ) -> tuple[tuple[GenomicAlnData, GenomicAlnData] | None, str | None]:
         """Get aligned genomic coordinates for transcript exon start and end.
 
         :param tx_ac: Transcript accession