Abstract: SA-PO413
Phenotypic Expression of Primary Hyperoxaluria: Comparative Features of Types 1, 2, and 3
Session Information
- Genetic Diseases of the Kidney - III
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1002 Genetic Diseases of the Kidneys: Non-Cystic
Authors
- Singh, Prince, Mayo Clinic, Rochester, Minnesota, United States
- Viehman, Jason K., Mayo Clinic, Rochester, Minnesota, United States
- Mehta, Ramila A., Mayo Clinic, Rochester, Minnesota, United States
- Hasadsri, Linda, Mayo Clinic, Rochester, Minnesota, United States
- Cogal, Andrea G., Mayo Clinic, Rochester, Minnesota, United States
- Sas, David J., Mayo Clinic, Rochester, Minnesota, United States
- Harris, Peter C., Mayo Clinic, Rochester, Minnesota, United States
- Lieske, John C., Mayo Clinic, Rochester, Minnesota, United States
- Milliner, Dawn S., Mayo Clinic, Rochester, Minnesota, United States
Background
Primary hyperoxalurias (PH) are inborn errors of metabolism that result from 3 specific hepatic enzyme deficiencies leading to hepatic overproduction of oxalate that must be excreted by the kidneys. Recurrent calcium oxalate kidney stones, nephrocalcinosis and decreased kidney function are common. PH type 3 (PH3) accounting for 10% of known PH cases was most recently described and hence the clinical expression is less defined due to small patient numbers and shorter follow-up.
Methods
Demographic and clinical data were obtained from patients enrolled in the Rare Kidney Stone Consortium PH registry. PH diagnosis was by molecular diagnostic testing of AGXT (PH1), GRHPR (PH2) and HOGA1 (PH3) genes. Demographic, clinical, and laboratory features were compared by PH type using a Chi-square test (categorical variables) and Kruskal-Wallis test (continuous variables).
Results
Though they tended to be younger at onset of symptoms and diagnosis, PH3 patients were more likely to have had stones prior to diagnosis (p=0.025), a lower prevalence of nephrocalcinosis (p=0.002), and lower urine oxalate, and higher urine calcium and citrate excretions than PH1 patients.(p <0.001) PH3 patients continued to experience recurrent stones throughout all decades of life. See Figure 1
Conclusion
Though more likely to have stones at presentation and higher urine calcium, nephrocalcinosis is less prevalent and kidney function better preserved in PH3 compared to PH1 and PH2. The lower Uox and higher urine citrate may contribute to preserved renal function, although the higher urine calcium may contribute to frequent stone events throughout the lifespan. The data suggest persistent stone activity throughout life in PH3 patients.
Boxplot Stone events per patient per year
Funding
- NIDDK Support