Genetics of congenital and infantile nephrotic syndrome

Abstract

Background: Congenital and infantile nephrotic syndrome (CNS and INS) are rare inherited defects in glomerular filtration involving a variety of gene mutations. This study aimed to analyze all genetic mutations associated with congenital and infantile nephrotic syndrome treated at our institution. We also discussed our different approach secondary to culture and resources.

Methods: A retrospective single-center study of all children diagnosed as NS before the age of 1 year over a duration of over one decade.

Results: Twenty-nine children (12 boys) were included in the study. Their median age (range) was 2.4 (0.1-12) months (20 CNS and 9 INS). Consanguinity was present in 90% of children. The genetic analysis' results were only available for 20 children. An underlying causative homozygous mutation was detected in 18 children (90%): NPHS1 (9), NPHS2(2), LAMB2(3), PLCE1(1), WT1(1), and ITSN1 novel mutation (2). One child had heterozygous mutation of NPHS2 and another child had heterozygous mutation of NPHS1 which could not explain the disease. All CNS cases were all managed with intermittent intravenous albumin infusion, ACEi, diuretics, and indomethacin. None of the children were managed by nephrectomy followed by peritoneal dialysis (PD) because of limited resources. Only one child achieved partial remission, while 15 children died at a median (range) age of 5.8 (1.25-29) months. The remaining 14 children were followed up for an average of 36 (3.9-120) months. Three children progressed to end-stage kidney disease and PD was performed in only two children.

Conclusions: NPHS1 is the main underlying cause of CNS and INS in our study population. CNS and INS were associated with high morbidity and mortality.

Keywords: Congenital nephrotic; Genetics; Infantile nephrotic; Outcome.