Phenotypes and genotypes underlying paradoxical pupillary reaction in children
1Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates, Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio.
Summary
Paradoxical pupillary reaction, a rare sign in inherited retinal disorders, was studied in children. Novel genetic causes and variable expressivity were identified, expanding our understanding of this pupillary response.
Area of Science:
- Ophthalmology
- Clinical Genetics
- Pediatric Retinal Diseases
Background:
- Paradoxical pupillary reaction (PPR), characterized by initial pupillary constriction in darkness, is primarily linked to congenital stationary night blindness and achromatopsia.
- The genetic underpinnings and associations of PPR with diverse pediatric retinal phenotypes remain incompletely understood.
Observation:
- A retrospective review identified four children with genetically confirmed PPR from four families at Cleveland Clinic Abu Dhabi (2016-2020).
- Patients presented with pathogenic variants in TRPM1 (congenital stationary night blindness), CABP4 (congenital cone-rod synaptic disorder), and PAX2 (papillorenal syndrome).
Findings:
- This study identified novel genotypes associated with PPR, including CABP4 and PAX2 variants, broadening the spectrum beyond TRPM1.
- Intrafamilial variable expressivity of PPR was observed in relatives with TRPM1-related congenital stationary night blindness, indicating inconsistent manifestation within families.
Implications:
- The findings expand the known genetic landscape of PPR in pediatric populations.
- Understanding these genetic associations is crucial for accurate diagnosis, genetic counseling, and potential therapeutic strategies for inherited retinal disorders.
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