Low prevalence of NPHS2 mutations in African American children with steroid-resistant nephrotic syndrome.
In African American (AA) children, focal segmental glomerulosclerosis (FSGS) is the leading cause of nephrotic syndrome (NS). It has been shown that AA children suffer from FSGS and steroid-resistant nephrotic syndrome (SRNS) at a higher frequency and with a more severe renal outcome in comparison with Caucasian children. Previous mutation analysis of large cohorts revealed that a high percentage of childhood SRNS is monogenic and that mutations in podocin (NPHS2) and Wilms' tumor gene 1 (WT1) account for approximately 30% of SRNS in children. To test whether AA children with SRNS have a similar or a higher mutation rate, we performed mutation analysis of NPHS2 and WT1 in a cohort of AA children with SRNS. Direct sequencing was carried out for all exons of NPHS2 and for exons 8 and 9 of WT1. We ascertained 18 children of AA descent in whom renal biopsy findings showed FSGS in 13 patients (72%) and minimal-change disease in five patients (28%). In both NPHS2 and WT1, no disease-causing mutations were detected. Our data strongly suggest that in AA children with SRNS, the frequency of NPHS2 mutations is much lower than in large cohorts of pediatric SRNS patients in the general population. Knowledge of mutation rate of NPHS2 in different populations of SRNS patients facilitates the physician in planning a suitable genetic screening strategy for patients.
Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA.
Gil
G
Chernin
Saskia F
SF
Heeringa
Rasheed
R
Gbadegesin
Jinhong
J
Liu
Bernward G
BG
Hinkes
Christopher N
CN
Vlangos
Virginia
V
Vega-Warner
Friedhelm
F
Hildebrandt
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D001741:Black or African American / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance; D005260:Female; D016162:Genes, Wilms Tumor; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D007668:Kidney / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation; D009404:Nephrotic Syndrome / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology
D000305:Adrenal Cortex Hormones; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein