title: [NPHS2 Mutation analysis study in children with steroid-resistant nephrotic syndrome].
abstract: Podocin is a protein located in the glomerular slit diaphragm where it takes part in the regulation of glomerular filtration. Mutations of the NPHS2 gene that codes podocin are the main cause of autosomal recessive steroid resistant nephrotic syndrome (SRNS).
  
  
  OBJECTIVE
  To identify the NPHS2 mutations in Chilean children with SRNS, and to determine the prevalence of the most common variants in a group of healthy adults.
  
  
  METHODS
  Mutation analysis of NPHS2 in 34 Chilean children with SRNS. Once the two most common variants of NPHS2 were identified, screening for these mutations was performed on 233 healthy adults. The mutation analysis was performed by the direct sequencing of the eight coding exons by polymerase chain reaction amplification. The DNA sequencing was performed using a fluorometric method, and then evaluated with SeqPilot software. The relationship between the presence of NPHS2 variants and SRNS was calculated by comparing the allele frequency between patients with SRNS and those of the healthy volunteers using the exact Fisher test. A P<.05 was considered significant.
  
  
  RESULTS
  Pathogenic NPHS2 mutations were detected in 7 (21%) of the 34 patients studied, of which 6 were heterozygotes for p.R229Q and p.A284V. The presence of p.R229Q was 2.46% in the healthy volunteers.
  
  
  CONCLUSIONS
  This study shows that p.R229Q and p.A284V are the most frequent variants in Chilean children with SRNS. It is the first time that this relationship has been reported in Chilean children. Based on this, a screening strategy is proposed for the genetic study in patients with SRNS and their families. A parallel or sequential search strategy for p.R229Q and p.A284V in these patients is proposed.
authors.affiliation: Unidad de Nefrología, Servicio de Pediatría, Hospital Luis Calvo Mackenna, Departamento Pediatría y Cirugía Infantil Oriente, Facultad de Medicina, Universidad de Chile, Santiago, Chile. Electronic address: maazocar@med.uchile.cl.
authors.forename: Marta
authors.initials: M
authors.lastname: Azocar
authors.affiliation: Programa de Doctorado en Ciencias Médicas asociado a Especialidad Clínica (Pediatría), Facultad de Medicina, Universidad de Chile, Hospital Luis Calvo Mackenna, Santiago, Chile.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Vega
authors.affiliation: Laboratorio de Biología Molecular, Hospital Luis Calvo Mackenna, Departamento de Pediatría Oriente, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Farfán
authors.affiliation: Unidad de Nefrología, Servicio de Pediatría, Hospital Luis Calvo Mackenna, Departamento Pediatría y Cirugía Infantil Oriente, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Cano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002677:Chile; D003430:Cross-Sectional Studies; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D005470:Fluorometry; D005787:Gene Frequency; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D009404:Nephrotic Syndrome / Q000151:congenital* / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein
keywords: Corticorresistencia; Diafragma de filtración glomerular; Glomerular slit diaphragm; NPHS2; Nephrotic syndrome; Podocin; Podocina; Steroid-resistant; Síndrome nefrótico