title: Whole-exome capture and sequencing identifies HEATR2 mutation as a cause of primary ciliary dyskinesia.
abstract: Motile cilia are essential components of the mucociliary escalator and are central to respiratory-tract host defenses. Abnormalities in these evolutionarily conserved organelles cause primary ciliary dyskinesia (PCD). Despite recent strides characterizing the ciliome and sensory ciliopathies through exploration of the phenotype-genotype associations in model organisms, the genetic bases of most cases of PCD remain elusive. We identified nine related subjects with PCD from geographically dispersed Amish communities and performed exome sequencing of two affected individuals and their unaffected parents. A single autosomal-recessive nonsynonymous missense mutation was identified in HEATR2, an uncharacterized gene that belongs to a family not previously associated with ciliary assembly or function. Airway epithelial cells isolated from PCD-affected individuals had markedly reduced HEATR2 levels, absent dynein arms, and loss of ciliary beating. MicroRNA-mediated silencing of the orthologous gene in Chlamydomonas reinhardtii resulted in absent outer dynein arms, reduced flagellar beat frequency, and decreased cell velocity. These findings were recapitulated by small hairpin RNA-mediated knockdown of HEATR2 in airway epithelial cells from unaffected donors. Moreover, immunohistochemistry studies in human airway epithelial cells showed that HEATR2 was localized to the cytoplasm and not in cilia, which suggests a role in either dynein arm transport or assembly. The identification of HEATR2 contributes to the growing number of genes associated with PCD identified in both individuals and model organisms and shows that exome sequencing in family studies facilitates the discovery of novel disease-causing gene mutations.
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Amjad
authors.initials: A
authors.lastname: Horani
authors.forename: Todd E
authors.initials: TE
authors.lastname: Druley
authors.forename: Maimoona A
authors.initials: MA
authors.lastname: Zariwala
authors.forename: Anand C
authors.initials: AC
authors.lastname: Patel
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Levinson
authors.forename: Laura G
authors.initials: LG
authors.lastname: Van Arendonk
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Thornton
authors.forename: Joe C
authors.initials: JC
authors.lastname: Giacalone
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Albee
authors.forename: Kate S
authors.initials: KS
authors.lastname: Wilson
authors.forename: Emily H
authors.initials: EH
authors.lastname: Turner
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Nickerson
authors.forename: Jay
authors.initials: J
authors.lastname: Shendure
authors.forename: Philip V
authors.initials: PV
authors.lastname: Bayly
authors.forename: Margaret W
authors.initials: MW
authors.lastname: Leigh
authors.forename: Michael R
authors.initials: MR
authors.lastname: Knowles
authors.forename: Steven L
authors.initials: SL
authors.lastname: Brody
authors.forename: Susan K
authors.initials: SK
authors.lastname: Dutcher
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Ferkol
mesh_terms: D000328:Adult; D056444:Axonemal Dyneins; D002648:Child; D016825:Chlamydomonas reinhardtii / Q000235:genetics; D025063:Chromosome Disorders / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D059472:Exome; D005260:Female; D005808:Genes, Recessive; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D007619:Kartagener Syndrome / Q000235:genetics* / Q000378:metabolism; D008297:Male; D020125:Mutation, Missense; D011506:Proteins / Q000235:genetics*; D012137:Respiratory System / Q000378:metabolism; D017422:Sequence Analysis, DNA / Q000379:methods; D055815:Young Adult
chemical_list: C578870:DNAAF5 protein, human; D011506:Proteins; D056444:Axonemal Dyneins