Vignette-Based Reflections to Inform Genetic Testing Policies in Living Kidney Donors.

Family history of kidney disease increases risk of end-stage kidney disease (ESKD) in donors. Pre-donation genetic testing is recommended in evaluation guidelines and regulatory policy. Collaborating across several institutions, we describe cases to illustrate the utility as well as practical issues in incorporating genetic testing in transplant protocols. Case 1 is from 2009, before pervasive genetic testing. A healthy 27-year-old Caucasian male had an uneventful donor evaluation for his mother, who had early onset ESKD of unclear cause. He participated in paired-exchange kidney donation, but developed progressive kidney disease and gout over the next 10 years. A uromodulin gene mutation (NM_003361.3(UMOD):c.377 G>A p.C126Y) was detected and kidney biopsy showed tubulointerstitial kidney disease. The patient subsequently required kidney transplantation himself. Case 2 was a 36-year-old African American female who had an uneventful kidney donor evaluation. She underwent gene panel-based testing to rule out ApolipoproteinL1 risk variants, for which was negative. Incidentally, a sickle-cell trait (NM_000518.5(HBB):c.20A>T p.Glu7Val) was noted, and she was declined for kidney donation. This led to significant patient anguish. Case 3 was a 26-year-old Caucasian female who underwent panel-based testing because the potential recipient, her cousin, carried a variant of uncertain significance in the hepatocyte nuclear factor-1-ß (HNF1B) gene. While the potential donor did not harbor this variant, she was found to have a likely pathogenic variant in complement factor I (NM_000204.4(CFI):c.1311dup:p.Asp438Argfs*8), precluding kidney donation. Our cases emphasize that while genetic testing can be invaluable in donor evaluation, transplant centers should utilize detailed informed consent, develop care pathways for secondary genetic findings, and share experience to develop best practices around genetic testing in donors.

A Rare Case of Calciphylaxis in an Orthotopic Liver Transplant Recipient with Acute Kidney Injury.

Calciphylaxis is a rare disease characterized by calcification of small- to medium-sized blood vessels in the dermis and subcutaneous fat, resulting in cutaneous necrosis. Although most commonly shown in patients with end-stage kidney disease, it has also been reported in patients with other diseases, including alcoholic cirrhosis and malignancies. Here, we report an unusual case of calciphylaxis in an orthotopic liver transplant recipient with acute kidney injury. The patient, a 43-year-old white female with a history of type 2 diabetes mellitus, alcoholic cirrhosis, and normal kidney function, presented with decompensated liver disease and hepatorenal syndrome; she no longer responded to medical treatment and required treatment with dialysis. Ten days after admission, she underwent liver transplant, resulting in improved liver function tests. She had acute tubular necrosis (creatinine peak: 325 µmol/L) from sustained hypotension during and after surgery, which required 4 sessions of dialysis over 2weeks. Six weeks after her transplant, she developed painful, nonulcerating, erythematous plaques over her shins and thighs. Skin biopsy of the lesions showed calciphylaxis, calcium deposits, and thrombotic vasculopathy. She also developed severe hypercalcemia (calcium level of 2.75 mmol/L) from immobility, which required treatment with a bisphosphonate and hemodialysis. The lesions improved 6 weeks later, and her renal function returned to normal. Calciphylaxis diagnosed in an orthotopic liver transplant recipient with acute kidney injury has not been previously reported. We hypothesize that her chronic inflammatory state caused down-regulation and low levels of fetuin A and protein C. She also had other risk factors, including hypoalbuminemia, obesity, systemic glucocorticoids, and alcoholic liver disease. Calciphylaxis can occur in patients with alcoholic cirrhosis and acute renal failure even after liver transplant. Further studies into the pathogenesis of this disease may help us understand why it develops in these patients and not others with the same risk factors.

De Novo Thrombotic Microangiopathy Immediately After Kidney Transplant in Patients Without Apparent Risk Factors.

Thrombotic microangiopathy refers to a spectrum of conditions that share a common underlying pathologic mechanism that result in endothelial damage and microangiopathic hemolytic anemia. De novo thrombotic microangiopathy after kidney transplant is often triggered by immunosuppressive drugs, and studies most often implicate calcineurin inhibitors and/or mammalian target of rapamycin inhibitors; however, muromonab and alemtuzumab also reportedly cause thrombotic microangiopathy. In addition, thrombotic microangiopathy may be triggered by acute antibody-mediated rejection and infections like cytomegalovirus and parvovirus. Here, we present a case series of 3 patients without any apparent risk factors (eg, acute antibody-mediated rejection) who developed de novo thrombotic microangiopathy immediately following kidney transplant, but before the introduction of calcineurin inhibitors. Two of these 3 patients were successfully managed with plasma exchange, and calcineurin inhibitors were successfully introduced without the recurrence of thrombotic microangiopathy.

Lower magnesium level associated with new-onset diabetes and pre-diabetes after kidney transplantation.

BACKGROUND: Hypomagnesemia is associated with increased peripheral insulin resistance in the general population. It is frequently seen after renal transplantation. We examined its role as a risk factor for new-onset diabetes after transplantation (NODAT) and new-onset pre-diabetes after transplantation (NOPDAT). METHODS: A retrospective analysis of 138 previously non-diabetic renal transplant recipients was conducted. Cox and logistic regression analyses were performed to examine the associations between 1-month post-transplant serum magnesium level and subsequent diagnoses of NODAT/NOPDAT. RESULTS: NODAT was diagnosed in 34 (24.6 %) and NOPDAT in 12 (8.7 %) patients. Median time to diagnosis of NODAT/NOPDAT was 20.4 months (interquartile range [IQR] 6.8-34.8). Median follow up for the entire group was 3.5 years (IQR 2.3-5.6). Mean magnesium level at 1 month after transplantation was significantly lower in patients subsequently diagnosed with NODAT/NOPDAT (1.60 ± 0.27 vs. 1.76 ± 0.29 mg/dl, p = 0.002). Cox regression analysis identified a trend towards developing NODAT/NOPDAT with lower baseline magnesium levels (hazard ratio 0.89 per 0.1 mg/dl increment in magnesium level, 95 % confidence interval [CI] = 0.78-1.01, p = 0.07); a stronger relationship between the two variables was seen at logistic regression analysis (odds ratio 0.81 per 0.1 mg/dl increment in serum magnesium (95 % CI 0.67-0.98, p = 0.03). CONCLUSIONS: A lower magnesium level at 1 month after transplantation may be predictive of a subsequent diagnosis of glucose intolerance or diabetes in renal transplant recipients. Whether replenishing magnesium stores can prevent development of these disorders requires further investigation.