title: Association between NEDD4L gene and sodium lithium countertransport.
abstract: BACKGROUND
  Sodium lithium countertransport (SLC) is an intermediate phenotype of essential hypertension. The aim of this study was to identify candidate genes for SLC by a strategy of combining gene expression profiling and linkage analysis, and to examine the association between the candidate gene and SLC as well as hypertension.
  
  
  METHODS
  In order to identify SLC-related genes, the top 1% of the genes that were differentially expressed between high- and low-SLC groups in a gene expression microarray were compared with published SLC/hypertension gene linkage maps so as to identify regions of overlap. The association between the genetic variation in the candidate gene and the SLC and blood pressure phenotypes were further assessed in the Rochester Family Heart Study (RFHS) involving 1,815 individuals of European ancestry, belonging to 252 pedigrees.
  
  
  RESULTS
  Based on gene expression profiling and evidence from genome-wide linkage analysis, and in the light of its potential biochemical function, E3 ubiquitin-protein ligase NEDD4-like (NEDD4L) was identified as being both a positional and a functional candidate gene for SLC. The difference in expressions of NEDD4L between the high- and low-SLC groups was confirmed by reverse transcription-PCR (RT-PCR) analysis. After adjusting for age, sex, and body mass index (BMI), four single-nucleotide polymorphisms (SNPs) in NEDD4L were found to be associated with SLC (P ≤ 0.05). Further, haplotype analysis revealed that, after correction for multiple testing, one of the haplotypes (H2) was still significantly (P = 0.006) associated with SLC.
  
  
  CONCLUSIONS
  The strategy of combining gene expression profiling and linkage analysis successfully guided us in identifying NEDD4L as a candidate gene involved in regulating SLC activity. Variations in the NEDD4L gene are associated with SLC activity.
authors.affiliation: Department of Human Genetics, University of Pittsburgh, Pennsylvania, USA.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Zheng
authors.forename: Alanna C
authors.initials: AC
authors.lastname: Morrison
authors.forename: Eleanor
authors.initials: E
authors.lastname: Feingold
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Turner
authors.forename: Robert E
authors.initials: RE
authors.lastname: Ferrell
mesh_terms: D017920:Antiporters / Q000235:genetics* / Q000378:metabolism; D001794:Blood Pressure / Q000235:genetics*; D016009:Chi-Square Distribution; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D006973:Hypertension / Q000201:enzymology / Q000208:ethnology / Q000235:genetics* / Q000503:physiopathology; D015810:Linkage Disequilibrium; D008910:Minnesota; D000075702:Nedd4 Ubiquitin Protein Ligases; D010375:Pedigree; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018570:Risk Assessment; D012307:Risk Factors; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D044465:White People / Q000235:genetics
chemical_list: D017920:Antiporters; D056827:Endosomal Sorting Complexes Required for Transport; C045885:sodium-lithium countertransporter; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; C000618485:Nedd4L protein, human; D044767:Ubiquitin-Protein Ligases