Mutational analysis of NPHS2 and WT1 in frequently relapsing and steroid-dependent nephrotic syndrome.
Idiopathic nephrotic syndrome is a common pediatric kidney disease, 80% of all cases are steroid sensitive (SSNS). A significant proportion of children with SSNS will have a frequently relapsing or steroid-dependent course (FRNS/SDNS) that is associated with significant treatment-related morbidity. Mutations in NPHS2 account for more than 28% of all cases of steroid-resistant nephrotic syndrome (SRNS) and dominant mutations in WT1 for 5%; while mutations are absent from children with uncomplicated SSNS. Since FRNS/SDNS is phenotypically positioned within a spectrum between SSNS and SRNS, we hypothesized that heterozygous mutations of NPHS2 may be causing FRNS/SDNS. Mutational analysis of NPHS2 and WT1 was carried out in a single-center cohort of 20 children with FRNS/SDNS, ten children with uncomplicated SSNS (control), and 22 children with SRNS (control). Renal biopsy findings were available in 15/20 children with FRNS/SDNS and revealed IgM nephropathy, MCNS, and FSGS in six, five, and four children, respectively. Children with FRNS/SDNS were significantly younger at first presentation than those with SSNS and SRNS (median age: 3.0 years in FRNS/SDNS patients, 7.0 years in SSNS patients, and 5.0 in SRNS patients; p < 0.001). No NPHS2 or WT1 mutations were found in patients with FRNS/SDNS and uncomplicated SSNS. The hypothesis that FRNS/SDNS may be associated with heterozygous mutations in NPHS2 or WT1 was not confirmed.
Gbadegesin
Rasheed
R
Department of Pediatrics, Division of Nephrology, Ann Arbor, MI 48109, USA.
Hinkes
Bernward
B
Vlangos
Christopher
C
Mucha
Bettina
B
Liu
Jinhong
J
Hopcian
Jeff
J
Hildebrandt
Friedhelm
F
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007223:Infant; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D009404:Nephrotic Syndrome / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012008:Recurrence; D013256:Steroids; D025721:WT1 Proteins / Q000235:genetics*
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein; D013256:Steroids; D025721:WT1 Proteins