Characteristics of Inherited Metabolic Disorders Following Kidney Transplantation: A 13-Year Observational Study

Background and Objectives: Inherited metabolic disorders (IMDs), primarily cystinosis, Fabry disease, and methylmalonic acidemia (MMA), are genetic conditions that typically result in multi-organ disease manifestations. Kidney function progressively deteriorates in many cases, with patients eventually reaching end-stage kidney disease (ESKD) and requiring renal replacement therapy. Kidney transplantation has been deemed the optimal renal replacement therapy option to achieve long-term survival in patients with IMD. Whilst improved long-term survival is expected, the patterns of clinical evolution for IMD after transplantation remain largely unknown. Methods: Our group conducted a retrospective observational study that included 37 adult patients with IMD (11 with cystinosis, 20 with Fabry disease, and 6 with MMA). The study evaluated the clinical status and progression of these patients following kidney transplantation between January 2010 and December 2023. Results: This generally resulted in good graft outcomes for patients with IMD. Standard immunosuppression regimes included tacrolimus, mycophenolate mofetil, and prednisolone. The mean graft survival duration was noted to be 12 years in patients with cystinosis, 11 years in patients with Fabry disease, and 7 years in patients with MMA. Suboptimal outcomes were noted with grafts of cadaveric origin and poor adherence to the prescribed post-transplant immunosuppression regime. A greater extra-renal morbidity burden was associated with a reduced duration of graft function and increased mortality in patients with IMD. Conclusions: Our findings emphasise the need for a multi-disciplinary approach in the care of IMD patients following kidney transplantation.