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Abstract: SA-PO579

UPLC-MS/MS-Based Plasma Assay for Therapeutic Monitoring in Patients With APRT Deficiency

Session Information

  • Genetic Diseases: Diagnosis
    November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

  • 1102 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Thorsteinsdottir, Unnur A., Heilbrigdisvisindasvid - Haskoli Island, Reykjavik, Iceland
  • Runolfsdottir, Hrafnhildur L., Landspitali, Reykjavik, Capital, Iceland
  • Edvardsson, Vidar O., Landspitali, Reykjavik, Iceland
  • Palsson, Runolfur, Landspitali, Reykjavik, Iceland
  • Thorsteinsdottir, Margret, Heilbrigdisvisindasvid - Haskoli Island, Reykjavik, Iceland

Group or Team Name

  • APRT Deficiency Research Program of the Rare Kidney Stone Consortium
Background

Adenine phosphoribosyltransferase deficiency (APRTd) is a rare disorder of purine metabolism characterized by urinary excretion of poorly soluble 2,8-dihydroxyadenine (DHA), nephrolithiasis and chronic kidney disease (CKD). Treatment with allopurinol or febuxostat, reduces DHA excretion and slows CKD progression. The aim was to optimize a UPLC-MS/MS method for simultaneous quantification of DHA, adenine, allopurinol, oxypurinol and febuxostat in plasma, utilizing the chemometric approach design of experiments (DoE).

Methods

The UPLC-MS/MS quantification method was optimized, employing the chemometric software MODDE Pro 13. Fractional factorial (FF) design was used to reveal significant experimental factors influencing peak area, retention time and resolution of all analytes using partial least square (PLS) regression. Absolute quantification of DHA, adenine, allopurinol, oxypurinol and febuxostat was performed in plasma samples from untreated and treated APRTd patients and healthy controls.

Results

For all analytes, accuracy and precision were within the acceptable range of ± 15%. Preliminary data revealed a median (range) plasma concentration of 248 (224-395) ng/mL for DHA and 194 (159-284) ng/mL for adenine, in the untreated patients, and below 50 ng/mL for DHA and 533 (339-1034) ng/mL for adenine, in those on treatment. DHA was not detected in the plasma samples from healthy controls. In patients receiving XOR inhibitor therapy, the median plasma concentration for allopurinol, oxypurinol and febuxostat was 687 (103-2901), 7945 (2199-10943) and 1628 ng/mL, respectively.

Conclusion

A UPLC-MS/MS assay for quantification of DHA, adenine, allopurinol, oxypurinol and febuxostat in human plasma was developed and optimized using DoE.

Funding

  • Government Support – Non-U.S.