Abstract: FR-PO750
Primary Hyperoxaluria Type 3 Diagnosed After Kidney Transplant
Session Information
- Post-Transplantation and Case Reports
November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 2102 Transplantation: Clinical
Authors
- Martin, Kirsten, MedStar Georgetown University Hospital, Washington, District of Columbia, United States
- Abdalla, Marwa, MedStar Georgetown University Hospital, Washington, District of Columbia, United States
- Nilubol, Chanigan, MedStar Georgetown University Hospital, Washington, District of Columbia, United States
Introduction
Primary hyperoxaluria (PH) is a group of genetic disorders that lead to increased hepatic production of oxalate. PH type 3 (PH3), the most recently identified subtype results from mutations in the mitochondrial 4-hydroxy-2-oxoglutarate aldolase gene (HOGA1). To date, there have been 3 cases of kidney failure reported in PH3 patients. Here we report a case of a man with recurrent kidney stones in his childhood who was diagnosed with PH3 late in life after receiving a kidney transplant.
Case Description
A 74-year-old Norwegian man with a history of recurrent kidney stones since infancy leading to left nephrectomy at the age of 12 presented with proteinuric chronic kidney disease (CKD). His eGFR based on serum Cr of 2.6 mg/dL was 23 ml/min/1.73m2. His urine protein-creatinine ratio was around 2 gm/gm. An ultrasound showed a 13.8 cm right kidney with 2 non-obstructing stones. His CKD was presumably due to secondary focal segmental glomerulosclerosis from adaptive hyperfiltration. Fifteen months later, he received a pre-emptive deceased donor kidney transplant out-of-state with an excellent allograft function. Due to the unclear diagnosis of his kidney disease, he completed a genetic testing panel which was positive for homozygous HOGA1 mutation. His 24-hr urine collection showed a mildly elevated oxalate level at 40 mg/day. This may have reflected his habitual dietary oxalate restriction since childhood. The differential diagnosis may have included oxalate nephropathy in his native kidney.
Discussion
Our case signifies the necessity of metabolic workup and genetic testing in patients with kidney stones, particularly in recurrent cases. PH3 was described as a less severe form of PH. Our case is unique in that despite his severe disease early in life, he did not progress into end-stage renal disease until 5 decades after his nephrectomy. Not until the recently FDA-approved Oxlumo (lumasiran), an RNA interference agent, as a medical therapy for PH type 1, the only curative treatment for PH had been a liver transplant or a combined liver/kidney transplant. While our patient may have missed the opportunity to receive a combined liver/kidney transplant, the impact of PH3 on his metabolic profile is mild and medically manageable. The RNA interference agents for PH type 2 and type 3 are being investigated but are not yet FDA-approved. Our patient may be a candidate for such therapy in the future.