Long-term outcome of congenital nephrotic syndrome after kidney transplantation in Japan

Congenital nephrotic syndrome is difficult to manage, particularly the Finnish type (CNF), with patients experiencing severe edema, sepsis and thrombosis before kidney transplantation. Further, nephrosis and thrombosis remain problematic after transplantation.

Of 22 CNF patients managed at our hospital, 14 who underwent kidney transplantation were retrospectively studied. CNF was diagnosed according to standard criteria.

The study population consisted of 3 males and 11 females. Mean gestation period was 36 ± 1.4 weeks and mean birth weight was 2442 ± 454 g (mean placenta to body weight ratio: 0.4). All patients started dialysis at 2.4 ± 1.3 years and underwent kidney transplantation at 5.2 ± 2.0 years. The kidneys were donated by the parents (n = 13), and cadaver (n = 2), including overlap. Mean follow-up period after transplantation was 14.3 ± 8.9 years, and mean age at last observation was 19.5 ± 8.5 years. Two patients had recurrent proteinuria after kidney transplantation; one underwent retransplantation following graft failure and eventually required dialysis, while the second had complete remission after intensive immunosuppressive therapy. There were no cases of thrombosis or serious infections. Mean eGFR at the time of last observation was 57.3 ± 16.5 ml/min/1.73 m², while mean height SD score was − 2.1 ± 0.9 at the time of transplantation and − 1.5 ± 1.5 at last observation.

Long-term outcome in these 14 CNF patients showed satisfactory graft survival, improved height SD score, and favorable development. Although recurrent proteinuria after transplant was not predictive, it was associated with graft survival rate.