title: Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome.
abstract: BACKGROUND
  In renal Fanconi's syndrome, dysfunction in proximal tubular cells leads to renal losses of water, electrolytes, and low-molecular-weight nutrients. For most types of isolated Fanconi's syndrome, the genetic cause and underlying defect remain unknown.
  
  
  METHODS
  We clinically and genetically characterized members of a five-generation black family with isolated autosomal dominant Fanconi's syndrome. We performed genomewide linkage analysis, gene sequencing, biochemical and cell-biologic investigations of renal proximal tubular cells, studies in knockout mice, and functional evaluations of mitochondria. Urine was studied with the use of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy.
  
  
  RESULTS
  We linked the phenotype of this family's Fanconi's syndrome to a single locus on chromosome 3q27, where a heterozygous missense mutation in EHHADH segregated with the disease. The p.E3K mutation created a new mitochondrial targeting motif in the N-terminal portion of EHHADH, an enzyme that is involved in peroxisomal oxidation of fatty acids and is expressed in the proximal tubule. Immunocytofluorescence studies showed mistargeting of the mutant EHHADH to mitochondria. Studies of proximal tubular cells revealed impaired mitochondrial oxidative phosphorylation and defects in the transport of fluids and a glucose analogue across the epithelium. (1)H-NMR spectroscopy showed elevated levels of mitochondrial metabolites in urine from affected family members. Ehhadh knockout mice showed no abnormalities in renal tubular cells, a finding that indicates a dominant negative nature of the mutation rather than haploinsufficiency.
  
  
  CONCLUSIONS
  Mistargeting of peroxisomal EHHADH disrupts mitochondrial metabolism and leads to renal Fanconi's syndrome; this indicates a central role of mitochondria in proximal tubular function. The dominant negative effect of the mistargeted protein adds to the spectrum of monogenic mechanisms of Fanconi's syndrome. (Funded by the European Commission Seventh Framework Programme and others.).
authors.affiliation: From the Centre for Nephrology (E.D.K., H.C.S., D.B., G.J., H.C., A.M.H., R.J.U., R.K.) and Institute of Child Health (D.B., R.K.), University College London, and Biomolecular Medicine, Imperial College London (S.L.R., A.D.W., E.H., J.K.N.) - both in London; the Departments of Medical Cell Biology (M.R., C.B., D.P., C.S., R. Warth), Internal Medicine III (K.R.), Internal Medicine II (S.W.R.), and Molecular and Cellular Anatomy (R. Witzgall) and the Institutes of Functional Genomics (J.R., K.E., N.A., P.J.O., K.D.) and Pathology (J.S.), University of Regensburg, and the Department of Radiology, Barmherzige Brueder Hospital (N.Z.) - all in Regensburg, Germany; the National Human Genome Research Institute (A.H.-W., S.L.R., H.C.S., K.O., I.B., D.M.K., W.A.G., R.K.) and National Heart, Lung, and Blood Institute (Y.I.), National Institutes of Health, Bethesda, MD; the Division of Pediatric Nephrology, University of Florida, Jacksonville (A.T., M.I.); the Genome Biology Department, Australian National University, Canberra, ACT, Australia (M.A.-B.); Kitasato University Medical Center, Saitama, Japan (H.N.); and the Department of Pathology, Northwestern University, Chicago (Y.J., J.K.R.).
authors.forename: Enriko D
authors.initials: ED
authors.lastname: Klootwijk
authors.forename: Markus
authors.initials: M
authors.lastname: Reichold
authors.forename: Amanda
authors.initials: A
authors.lastname: Helip-Wooley
authors.forename: Asad
authors.initials: A
authors.lastname: Tolaymat
authors.forename: Carsten
authors.initials: C
authors.lastname: Broeker
authors.forename: Steven L
authors.initials: SL
authors.lastname: Robinette
authors.forename: Joerg
authors.initials: J
authors.lastname: Reinders
authors.forename: Dominika
authors.initials: D
authors.lastname: Peindl
authors.forename: Kathrin
authors.initials: K
authors.lastname: Renner
authors.forename: Karin
authors.initials: K
authors.lastname: Eberhart
authors.forename: Nadine
authors.initials: N
authors.lastname: Assmann
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Oefner
authors.forename: Katja
authors.initials: K
authors.lastname: Dettmer
authors.forename: Christina
authors.initials: C
authors.lastname: Sterner
authors.forename: Josef
authors.initials: J
authors.lastname: Schroeder
authors.forename: Niels
authors.initials: N
authors.lastname: Zorger
authors.forename: Ralph
authors.initials: R
authors.lastname: Witzgall
authors.forename: Stephan W
authors.initials: SW
authors.lastname: Reinhold
authors.forename: Horia C
authors.initials: HC
authors.lastname: Stanescu
authors.forename: Detlef
authors.initials: D
authors.lastname: Bockenhauer
authors.forename: Graciana
authors.initials: G
authors.lastname: Jaureguiberry
authors.forename: Holly
authors.initials: H
authors.lastname: Courtneidge
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Hall
authors.forename: Anisha D
authors.initials: AD
authors.lastname: Wijeyesekera
authors.forename: Elaine
authors.initials: E
authors.lastname: Holmes
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Nicholson
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Brien
authors.forename: Isa
authors.initials: I
authors.lastname: Bernardini
authors.forename: Donna M
authors.initials: DM
authors.lastname: Krasnewich
authors.forename: Mauricio
authors.initials: M
authors.lastname: Arcos-Burgos
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Izumi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nonoguchi
authors.forename: Yuzhi
authors.initials: Y
authors.lastname: Jia
authors.forename: Janardan K
authors.initials: JK
authors.lastname: Reddy
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ilyas
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Unwin
authors.forename: William A
authors.initials: WA
authors.lastname: Gahl
authors.forename: Richard
authors.initials: R
authors.lastname: Warth
authors.forename: Robert
authors.initials: R
authors.lastname: Kleta
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D044383:Black People; D002893:Chromosomes, Human, Pair 3; D004195:Disease Models, Animal; D005198:Fanconi Syndrome / Q000208:ethnology / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010375:Pedigree; D063994:Peroxisomal Bifunctional Enzyme / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D017422:Sequence Analysis, DNA
chemical_list: C576253:EHHADH protein, human; D063994:Peroxisomal Bifunctional Enzyme