*Purpose: To demonstrate the role of simultaneous liver kidney transplant in PH2

*Methods: A 30-year-old white man presented to our center for evaluation of chronic kidney disease stage 4 secondary to primary hyperoxaluria type 2 (PH2). He had recurrent episodes of urolithiasis after age 18 yrs requiring 4 lithotripsy procedures, but a diagnosis of PH2 was not made until genetic testing at age 28 yrs identified two pathogenic variants in the glyoxylate reductase hydroxypyruvate reductase (GRHPR) gene [c.103delG (p.Asp35Thrfs*11); c.781_782delinsTAC (p.Gly261Tyrfs*2)]. His initial serum creatinine (SCr) at our center was 4.71 mg/dl (eGFR 18 ml/min/1.73 m²) with plasma oxalate (POx) of 21.9 µmol/l [normal <2] and urinary oxalate (UOx) of 228 mg/24 h [normal <41]. Urinary glycerate was markedly elevated at 197 mg/g Cr [normal < 25], consistent with PH2. Medications included potassium citrate, magnesium oxide and chlorthalidone. His kidney function progressively declined over the next 5 months at which time SCr was 8.79 mg/dl (eGFR 8 ml/min/1.73m²) and POx 28.8 µmol/l. Given the marked degree of hyperoxaluria and potential for recurrent oxalate nephropathy the patient underwent evaluation for simultaneous liver kidney (SLK) transplant, which he subsequently received 6 weeks after activation on the waiting list without ever requiring renal replacement therapy.

*Results: Both allografts had good initial function and the patient did not require post-surgical hemodialysis. POx fell from 39.6 preoperatively to 9.1 µmol/l 12 hours posttransplant, and then 6.8 µmol/l 36 hours later. POx remained <3 µmol/l through the most recent follow up 6 weeks after transplant. Correspondingly UOx decreased to 21 mg/24 h by 5 weeks after transplant and urinary glycerate normalized to 3 mg/g. SCr ranged between 1.86-2.01 mg/dl (eGFR 48-55 ml/min/1.73 m²) once stabilized after discharge. His postoperative course was complicated by recurrent ascites; transjugular hepatic venogram revealed mild narrowing of the intrahepatic inferior vena cava which has been managed conservatively to date.

*Conclusions: This case, together with 2 others in the literature, provides further evidence regarding SLK transplantation in PH2. Even though GRHPR has a wide tissue distribution, evidence suggests it is predominantly expressed in the liver, and as a group these 3 cases suggest liver transplantation can reduce oxalate generation to normal (non-PH2) levels. Thus, SLK transplant is a viable therapeutic option for select PH2 patients with advanced CKD.

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