diff --git a/src/meds/schema.py b/src/meds/schema.py
index cc503b3..e73732c 100644
--- a/src/meds/schema.py
+++ b/src/meds/schema.py
@@ -60,7 +60,7 @@ def patient_schema(per_event_properties_schema=pa.null(), per_patient_properties
     },
 )
 
-Patient = TypedDict("Patient", {"patient_id": int, "events": List[Event]})
+Patient = TypedDict("Patient", {"patient_id": int, "events": List[Event], "properties": NotRequired[Any]})
 
 ############################################################