Impact of Genetic Testing on the Outcome of Kidney Transplant Recipient Evaluation

Background: Identifying a genetic etiology during evaluation of kidney transplant (KT) candidates can inform the risk of disease recurrence, guide KT management, and enable the assessment of living related donors. Despite these benefits, there is limited literature on the impact of genetic testing on recipient candidate outcomes. Methods: Eighty patients who underwent KT evaluation in January 2021 to November 2022 were assessed. Patients with positive genetic test results were compared with patients without any identified kidney disease related genetic variants. The primary outcomes were waitlisting, KT and delayed graft function (DGF). Results: Positive genetic test results were found in 44 (55%) patients, with APOL1 high risk genotypes (20, 45%), PKD1/2 (6, 14%) and COL4A3-4 variants (4, 9%) being the most common. There were no significant differences between patients with positive and negative test results in terms of age, sex, self-identified race and cause of kidney disease. The criteria for testing are shown in Figure 1. During a median follow up of 2 yrs (IQR,1.75-2.58), 63% of the patients were waitlisted and 45% underwent KT. Waitlisting, deceased (DDKT) and living donor KT (LDKT) rates did not differ significantly between patients with positive and negative genetic results (Waitlisting: 28 (64%) vs 22 (61%),p=0.82; DDKT: 16 (36%) vs 14 (39%) and LDKT: 2 (5%) vs 3 (8%),p=0.58). DGF rates were similar between patients with positive and negative results (3 (7%) vs 3 (8%),p=0.59). Four patients with positive genetic test results developed biopsy confirmed rejection while no rejection episodes were recorded in patients with negative genetic results (p=0.039). Conclusion: In this pilot study, genetic testing with positive findings in KT evaluations did not significantly impact waitlisting, transplant and DGF risk of recipient candidates. Higher rate of rejection in patients with positive genetic test results needs further studies.