title: Identification and functional characterization of NODAL rare variants in heterotaxy and isolated cardiovascular malformations.
abstract: NODAL and its signaling pathway are known to play a key role in specification and patterning of vertebrate embryos. Mutations in several genes encoding components of the NODAL signaling pathway have previously been implicated in the pathogenesis of human left-right (LR) patterning defects. Therefore, NODAL, a member of TGF-beta superfamily of developmental regulators, is a strong candidate to be functionally involved in congenital LR axis patterning defects or heterotaxy. Here we have investigated whether variants in NODAL are present in patients with heterotaxy and/or isolated cardiovascular malformations (CVM) thought to be caused by abnormal heart tube looping. Analysis of a large cohort of cases (n = 269) affected with either classic heterotaxy or looping CVM revealed four different missense variants, one in-frame insertion/deletion and two conserved splice site variants in 14 unrelated subjects (14/269, 5.2%). Although similar with regard to other associated defects, individuals with the NODAL mutations had a significantly higher occurrence of pulmonary valve atresia (P = 0.001) compared with cases without a detectable NODAL mutation. Functional analyses demonstrate that the missense variant forms of NODAL exhibit significant impairment of signaling as measured by decreased Cripto (TDGF-1) co-receptor-mediated activation of artificial reporters. Expression of these NODAL proteins also led to reduced induction of Smad2 phosphorylation and impaired Smad2 nuclear import. Taken together, these results support a role for mutations and rare deleterious variants in NODAL as a cause for sporadic human LR patterning defects.
authors.affiliation: Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Bhagyalaxmi
authors.initials: B
authors.lastname: Mohapatra
authors.forename: Brett
authors.initials: B
authors.lastname: Casey
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Trang
authors.initials: T
authors.lastname: Ho-Dawson
authors.forename: Liana
authors.initials: L
authors.lastname: Smith
authors.forename: Susan D
authors.initials: SD
authors.lastname: Fernbach
authors.forename: Laura
authors.initials: L
authors.lastname: Molinari
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Niesh
authors.forename: John Lynn
authors.initials: JL
authors.lastname: Jefferies
authors.forename: William J
authors.initials: WJ
authors.lastname: Craigen
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Towbin
authors.forename: John W
authors.initials: JW
authors.lastname: Belmont
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Ware
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D019521:Body Patterning; D018376:Cardiovascular Abnormalities / Q000235:genetics* / Q000378:metabolism; D002648:Child; D015331:Cohort Studies; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D055457:Nodal Protein / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D051899:Smad2 Protein / Q000235:genetics / Q000378:metabolism; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C526007:NODAL protein, human; D055457:Nodal Protein; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; D051899:Smad2 Protein; D051900:Smad3 Protein