Nephrotic Syndrome in a Child With Mutation.

Steroid resistant nephrotic syndrome (SRNS) accounts for 30% of all cases of nephrotic syndrome (NS) in children and frequently leads to end stage kidney disease (ESKD). About 30% of children with SRNS demonstrate causative mutations in podocyte- associated genes. Early identification of genetic forms of SRNS is critical to avoid potentially harmful immunosuppressive therapy. A 2-year-old male patient with NS and no family history of renal disease did not respond to 4-week steroid treatment. Kidney biopsy demonstrated mesangial proliferative glomerulopathy with basement membrane dysmorphism. Tacrolimus and Lisinopril were added to therapy pending results of genetic testing. Kidney Gene panel showed a NPHS2 c.413G>A (p.Arg138Gln) homozygous pathogenic variant. This missense variant is considered a common pathogenic founder mutation in European populations. A diagnosis of autosomal-recessive form of nonsyndromic SRNS due to NPHS2 causative variant was made. Immunosuppresive therapy was stopped, Lizinopril dose was increased and weekly infusions of Albumin/furosemide were initiated to manage edema. This case demonstrates that early genetic testing in children with SRNS avoids prolonged potentially harmful immunosuppressive therapy, allows for timely genetic family counseling, and allows earlier consideration for future living related donor kidney transplantation.