The retinal phenotype in primary hyperoxaluria type 2 and 3.
Johannes Birtel1,2,3,4, Roselie M Diederen5, Philipp Herrmann6
1Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 9DU, UK. study-enquiry@outlook.com.
Pediatric Nephrology (Berlin, Germany)
|October 19, 2022
Summary
Retinal disease is rare in primary hyperoxalurias types 2 and 3 (PH2-3). Mild retinal changes may occur in PH2 with kidney failure, and genetic testing is crucial for accurate diagnosis.
Area of Science:
- Ophthalmology
- Medical Genetics
- Metabolic Disorders
Background:
- Primary hyperoxalurias (PH1-3) are inherited metabolic disorders causing excess oxalate production.
- Oxalate deposits can affect kidneys, bones, heart, and eyes, leading to vision loss in PH1.
- Retinal involvement in PH2 and PH3 has not been systematically studied.
Observation:
- 19 patients with genetically confirmed PH2 (n=7) and PH3 (n=12) underwent ophthalmic examinations.
- Most patients (18/19) showed no retinal oxalate deposits; visual acuity was generally good.
- One PH2 patient on dialysis with high oxalate levels had drusen-like deposits; two siblings with PH2 had retinal degeneration and vision loss, linked to a co-occurring NR2E3 retinal dystrophy.
Findings:
- Retinal disease is uncommon in PH2 and PH3, but mild changes can occur, particularly in PH2 patients with kidney failure.
- Elevated plasma oxalate levels in PH2 patients may increase systemic oxalosis risk.
- Co-occurrence of PH2 with other genetic retinal diseases, like NR2E3-associated retinal dystrophy, can complicate diagnosis.
Implications:
- Ophthalmic screening is important for PH2 and PH3 patients, especially those with kidney impairment.
- Distinguishing PH-related ocular manifestations from independent inherited retinal diseases requires deep phenotyping and genomic profiling.
- Understanding the spectrum of retinal disease in PH is vital for comprehensive patient management and genetic counseling.
