title: ABCB1 polymorphisms and steroid treatment in children with idiopathic nephrotic syndrome.
abstract: BACKGROUND
  The most common cause of nephrotic syndrome (NS) is idiopathic nephrotic syndrome (INS), also called nephrosis. Although most patients respond to steroid therapy, there is unequal response to treatment suggesting the involvement of genetic factors. The current study was conducted to evaluate the influence of two single nucleotide polymorphisms (SNPs) in ABCB1 (C3435T and C1236T) on the steroid treatment response in INS children.
  
  
  METHODS
  Genotyping of ABCB1 C3435T and C1236T polymorphisms by real time PCR were conducted on 120 INS children, 80 steroid sensitive (SS) and 40 steroid resistant (SR).
  
  
  RESULTS
  A significant difference in the distribution of ABCB1 C3435T and C1236T genotypes was observed between SS and SR patients. C1236T polymorphism was associated with steroid resistance in INS children (odds ratio: 2.27, 95 % confidence interval: 1.2-4.4; P = 0.012). The frequency of the T allele was significantly higher in SR than in SS patients (81.2 vs. 65.6%, respectively). The odds ratio for the C3435T polymorphism in response to steroid treatment was smaller than that of the polymorphism C1236T, and did not reach statistical significance (odds ratio: 1.1, 95 % confidence interval: 0.6-1.9; P = 0.77).
  
  
  CONCLUSIONS
  Our results suggested that C1236T polymorphism in ABCB1 gene was associated with steroid resistance. A higher proportion of SR children had C1236T TT genotype and T allele, these patients may require other therapeutic strategies.
authors.affiliation: a Faculty of Medicine, Medical Biochemistry Department , Menoufia University , Shebin El-Kom , Egypt.
authors.forename: Manal A
authors.initials: MA
authors.lastname: Safan
authors.affiliation: a Faculty of Medicine, Medical Biochemistry Department , Menoufia University , Shebin El-Kom , Egypt.
authors.forename: Nesreen G
authors.initials: NG
authors.lastname: Elhelbawy
authors.affiliation: b Faculty of Medicine, Pediatric Department , Menoufia University , Shebin El-Kom , Egypt.
authors.forename: Dina A
authors.initials: DA
authors.lastname: Midan
authors.affiliation: a Faculty of Medicine, Medical Biochemistry Department , Menoufia University , Shebin El-Kom , Egypt.
authors.forename: Heba F
authors.initials: HF
authors.lastname: Khader
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance / Q000235:genetics; D005260:Female; D005838:Genotype; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D008297:Male; D009404:Nephrotic Syndrome / Q000188:drug therapy / Q000235:genetics*; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D011239:Prednisolone / Q000627:therapeutic use; D060888:Real-Time Polymerase Chain Reaction
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D005938:Glucocorticoids; D011239:Prednisolone
keywords: ABCB1 gene; idiopathic nephrotic syndrome; real-time PCR