Background: Genetic mutation of specific genes is the common cause of end stage renal disease (ESRD) in children, and nephronophthisis (NPHP) is the most common genetic cause of ESRD in children. Kidney transplantation is selected as the treatment of choice for pediatric ESRD patients with nephronophthisis. Nevertheless, long term outcome of kidney transplantation in NPHP patients remains uncertain and there are few data on the survival of the transplants in children. This study aims to analyze the long-term outcome of kidney transplantation in pediatric NPHP patients.  
Materials and Methods: A retrospective chart review was performed including pediatric patients with ESRD undergoing kidney transplantation at our hospital from January 2000-August 2018. Propensity score matching was done to compare graft survival of NPHP transplants with those of non-NPHP, using covariates of age, sex, weight, and transplant type (living or deceased). Total 23 NPHP and 46 non-NPHP were matched and the Kaplan-Meier analysis was performed.
Results and Discussion: Of 291 patients, common genetic diseases included 23 (7.9%) cases of NPHP, 8 (2.9%) of polycystic kidney disease, 2 (0.7%) of renal-coloboma syndrome, 4 (1.3%) of Denys-Drash syndrome, and 254(87.3%) of other causes of ESRD. For NPHP patients, 17 (73.9%) received a living donor kidney, and 6 (26.1%) a cadaveric donor kidney. The average age of receiving transplantation was 9.3 4.5 years. The median follow-up duration was 114 months for NPHP patients. There was no recurrence in our patients. There were 9 acute rejection and 2 graft failures during follow-up which showed 95.5% of 10-year graft survival rate. The cause of graft failure was acute rejection and chronic rejection each.
To minimize the selection bias, propensity score matching was done with NPHP and non-NPHP groups by 1:2 ratios. Five year graft survival rates were 95.5% and 94.7% for NPHP and non-NPHP, respectively. Ten year graft survival rates were 95.5% and 86.8% with p-value of 0.549 which showed no statistical significance. This results shows favorable outcome of kidney transplants in pediatric NPHP patients, when compared to general pediatric kidney transplant population.
Conclusions: Kidney transplantation in pediatric NPHP patients usually have good long-term outcomes and does not pose any specific challenges.