Monogenic variants drive low recurrence risk in pediatric steroid-resistant nephrotic syndrome after kidney transplantation: a high-consanguinity cohort.

Abstract

Background: Steroid-resistant nephrotic syndrome (SRNS) is a leading cause of stage 5 chronic kidney disease (CKD 5) in children and carries a substantial risk of post-transplant disease recurrence. Data from the Arabian Peninsula are sparse.

Methods: This retrospective cohort study included all paediatric patients (aged < 18 years) who underwent a first kidney transplant at King Fahad Specialist Hospital-Dammam between January 2008 and December 2023 with a confirmed diagnosis of SRNS, focal segmental glomerulosclerosis (FSGS), congenital nephrotic syndrome, or a pathogenic monogenic variant known to cause SRNS. Patients were classified as having genetic or non-genetic SRNS according to next-generation sequencing results. Primary outcomes were post-transplant recurrence rate and graft survival. Secondary outcomes included estimated glomerular filtration rate (eGFR) values and treatment response.

Results: Among 208 paediatric kidney transplant recipients, 60 (28.8%) had CKD 5 attributable to SRNS/FSGS. Genetic testing (performed in 59/60 patients, 98.3%) identified pathogenic variants in 44 patients (74.6%); NPHS2 was most prevalent (28.8%). Post-transplant recurrence occurred in 6 patients (10%): 5 of 15 in the non-genetic group (33%) and 1 of 44 in the genetic group (2.3%) (p < 0.001). All six patients with recurrence received plasmapheresis; five also received rituximab. Complete remission was achieved in 5 patients (83%) and partial remission in 1 (17%). The 5-year graft survival rate was 98% overall-100% in the genetic group versus 93% in the non-genetic group (log-rank p = 0.21). The eGFR at 5 years was significantly higher in the genetic group (73.5 ± 17.6 vs. 60.6 ± 22.9 mL/min/1.73 m², p = 0.049).

Conclusions: SRNS/FSGS accounts for approximately 29% of paediatric CKD 5 in this cohort and is characterised by a high prevalence of monogenic variants reflecting regional consanguinity. Genetic testing reliably stratifies recurrence risk: non-genetic SRNS carries a substantially higher recurrence rate, yet combined plasmapheresis and rituximab achieves remission in most affected patients. Graft outcomes are comparable to those seen in other CKD 5 aetiologies.