Genetic testing in the assessment of living related kidney donors at risk of autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic cause of renal failure. In most patients who develop end-stage renal disease, transplantation is the renal replacement modality of choice. For living related kidney donation (LRKD), the major challenge is to exclude the diagnosis of ADPKD in potential donors. Renal imaging may not exclude ADPKD particularly in younger donors and molecular genetic testing is advised. We report the largest series to date evaluating the role of genetic testing for ADPKD in LRKD assessment.

METHODS: A cohort of patients with ADPKD and potential LRKD were referred for genetic testing for ADPKD between April 2010 and October 2012. DNA sequencing of PKD1 and PKD2 was performed. Imaging investigations and transplant outcomes after genetic testing were collected.

RESULTS: Nineteen patients and 25 potential LRKD underwent genetic testing. Of potential LRKD, one tested positive for ADPKD and one with a diagnostic ultrasound tested negative. Despite negative genetic testing, two potential LRKD were considered unsuitable because of the detection of stage I ("simple") renal cysts on computed tomography. Four living related kidney transplants have occurred, and two are planned. Three patients subsequently refused the donation as the potential donor was a child.

CONCLUSION: Predictive genetic testing can facilitate donor evaluation and augment living related kidney transplantation in ADPKD. Psychologic challenges associated with accepting an LRKD require careful consideration during recipient assessment. The acceptability of using a kidney with cysts from a mutation-negative donor should be evaluated by a multidisciplinary team.