title: NPHP4 variants are associated with pleiotropic heart malformations.
abstract: BACKGROUND
  Congenital heart malformations are a major cause of morbidity and mortality, especially in young children. Failure to establish normal left-right (L-R) asymmetry often results in cardiovascular malformations and other laterality defects of visceral organs.
  
  
  OBJECTIVE
  To identify genetic mutations causing cardiac laterality defects.
  
  
  RESULTS
  We performed a genome-wide linkage analysis in patients with cardiac laterality defects from a consanguineous family. The patients had combinations of defects that included dextrocardia, transposition of great arteries, double-outlet right ventricle, atrioventricular septal defects, and caval vein abnormalities. Sequencing of positional candidate genes identified mutations in NPHP4. We performed mutation analysis of NPHP4 in 146 unrelated patients with similar cardiac laterality defects. Forty-one percent of these patients also had laterality defects of the abdominal organs. We identified 8 additional missense variants that were absent or very rare in control subjects. To study the role of nphp4 in establishing L-R asymmetry, we used antisense morpholinos to knockdown nphp4 expression in zebrafish. Depletion of nphp4 disrupted L-R patterning as well as cardiac and gut laterality. Cardiac laterality defects were partially rescued by human NPHP4 mRNA, whereas mutant NPHP4 containing genetic variants found in patients failed to rescue. We show that nphp4 is involved in the formation of motile cilia in Kupffer's vesicle, which generate asymmetrical fluid flow necessary for normal L-R asymmetry.
  
  
  CONCLUSIONS
  NPHP4 mutations are associated with cardiac laterality defects and heterotaxy. In zebrafish, nphp4 is essential for the development and function of Kupffer's vesicle cilia and is required for global L-R patterning.
authors.affiliation: Department of Clinical Genetics, Erasmus MC Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: French
authors.forename: Ingrid M B H
authors.initials: IM
authors.lastname: van de Laar
authors.forename: Marja W
authors.initials: MW
authors.lastname: Wessels
authors.forename: Christan
authors.initials: C
authors.lastname: Rohe
authors.forename: Jolien W
authors.initials: JW
authors.lastname: Roos-Hesselink
authors.forename: Guangliang
authors.initials: G
authors.lastname: Wang
authors.forename: Ingrid M E
authors.initials: IM
authors.lastname: Frohn-Mulder
authors.forename: Lies-Anne
authors.initials: LA
authors.lastname: Severijnen
authors.forename: Bianca M
authors.initials: BM
authors.lastname: de Graaf
authors.forename: Rachel
authors.initials: R
authors.lastname: Schot
authors.forename: Guido
authors.initials: G
authors.lastname: Breedveld
authors.forename: Edwin
authors.initials: E
authors.lastname: Mientjes
authors.forename: Marianne
authors.initials: M
authors.lastname: van Tienhoven
authors.forename: Elodie
authors.initials: E
authors.lastname: Jadot
authors.forename: Zhengxin
authors.initials: Z
authors.lastname: Jiang
authors.forename: Annemieke
authors.initials: A
authors.lastname: Verkerk
authors.forename: Sigrid
authors.initials: S
authors.lastname: Swagemakers
authors.forename: Hanka
authors.initials: H
authors.lastname: Venselaar
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Rahimi
authors.forename: Hossein
authors.initials: H
authors.lastname: Najmabadi
authors.forename: Hanne
authors.initials: H
authors.lastname: Meijers-Heijboer
authors.forename: Esther
authors.initials: E
authors.lastname: de Graaff
authors.forename: Wim A
authors.initials: WA
authors.lastname: Helbing
authors.forename: Rob
authors.initials: R
authors.lastname: Willemsen
authors.forename: Koen
authors.initials: K
authors.lastname: Devriendt
authors.forename: John W
authors.initials: JW
authors.lastname: Belmont
authors.forename: Ben A
authors.initials: BA
authors.lastname: Oostra
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Amack
authors.forename: Aida M
authors.initials: AM
authors.lastname: Bertoli-Avella
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015331:Cohort Studies; D005260:Female; D058685:Genetic Pleiotropy / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D055106:Genome-Wide Association Study / Q000379:methods*; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010375:Pedigree; D011506:Proteins / Q000235:genetics*; D015027:Zebrafish
chemical_list: C491578:NPHP4 protein, human; D011506:Proteins