Category: Vocabulary Users Title: ICD10CM G23.1 maps to sibling SNOMED concept, unreachable from PSP ancestor via CONCEPT_ANCESTOR
Hi all,
I’ve run into what I believe is a hierarchy gap affecting Progressive Supranuclear Palsy (PSP) cohort definitions. Posting here since GitHub issue creation appears to be suspended.
The Problem
When using CONCEPT_ANCESTOR to build a PSP cohort anchored at concept 40391011 (“Progressive supranuclear palsy,” SNOMED 192976002), ICD-10-CM code G23.1 is not reachable through the hierarchy.
G23.1 maps to a different SNOMED concept — 4103534 (“Progressive supranuclear ophthalmoplegia”) — which is a sibling of 40391011, not a descendant or ancestor. They share parents (Ophthalmoplegia, Cerebral degeneration) but have no direct hierarchical relationship.
Clinically these are the same disease. Steele-Richardson-Olszewski syndrome is the eponymous name for PSP. G23.1 is the only ICD-10-CM billing code available for PSP in the US. Any CONCEPT_ANCESTOR-based cohort definition anchored at 40391011 will return zero patients from claims or EHR data coded with G23.1.
Current State
| Concept ID | Name | Vocabulary | Standard |
|---|---|---|---|
| 40391011 | Progressive supranuclear palsy | SNOMED (192976002) | S |
| 4103534 | Progressive supranuclear ophthalmoplegia | SNOMED | S |
| 35207337 | Progressive supranuclear ophthalmoplegia [Steele-Richardson-Olszewski] | ICD10CM (G23.1) | — |
Current mapping: 35207337 (G23.1) --[Maps to]--> 4103534
Missing: Any relationship between 40391011 and 4103534.
Reproduction
-- Returns 0 rows: G23.1 is unreachable from PSP ancestor
SELECT *
FROM concept_ancestor ca
JOIN concept_relationship cr
ON cr.concept_id_2 = ca.descendant_concept_id
AND cr.relationship_id = 'Maps to'
JOIN concept c
ON c.concept_id = cr.concept_id_1
AND c.vocabulary_id = 'ICD10CM'
AND c.concept_code = 'G23.1'
WHERE ca.ancestor_concept_id = 40391011;
Possible Fixes
- Add a hierarchical “Is a” from 4103534 to 40391011 (ophthalmoplegia is a presentation of the palsy, not a separate disease)
- Add a second “Maps to” from G23.1 to 40391011
- Merge concepts if they are considered synonymous
Context
Discovered this during a feasibility assessment for a movement disorder biobank. We used CONCEPT_ANCESTOR from 8 neurodegenerative ancestor concepts to classify patients. Seven of eight categories resolved correctly. PSP was the only failure — 897 patients exist in our system under G23.1 but are invisible to a hierarchy-based query from 40391011.
Our workaround is supplementing the hierarchy query with a direct G23.1 filter, but this defeats the purpose of using the hierarchy and may affect any ATLAS cohort definition anchored at this concept.
Vocabulary version: v20260227 (February 2026 Athena release)
Thanks for any guidance. Happy to provide additional detail.
Roger Carlson Corewell Health Research Institute
