A Mutation in VWA1, Encoding von Willebrand Factor A Domain-Containing Protein 1, Is Associated With Hemifacial Microsomia

Abstract

Background: Hemifacial microsomia (HFM) is a type of rare congenital syndrome caused by developmental disorders of the first and second pharyngeal arches that occurs in one out of 5,600 live births. There are significant gaps in our knowledge of the pathogenic genes underlying this syndrome. Methods: Whole exome sequencing (WES) was performed on five patients, one asymptomatic carrier, and two marry-in members of a five-generation pedigree. Structure of WARP (product of VWA1) was predicted using the Phyre2 web portal. In situ hybridization and vwa1-knockdown/knockout studies in zebrafish using morpholino and CRISPR/Cas9 techniques were performed. Cartilage staining and immunofluorescence were carried out. Results: Through WES and a set of filtration, we identified a c.G905A:p.R302Q point mutation in a novel candidate pathogenic gene, VWA1. The Phyre2 web portal predicted alterations in secondary and tertiary structures of WARP, indicating changes in its function as well. Predictions of protein-to-protein interactions in five pathways related to craniofacial development revealed possible interactions with four proteins in the FGF pathway. Knockdown/knockout studies of the zebrafish revealed deformities of pharyngeal cartilage. A decrease of the proliferation of cranial neural crest cells (CNCCs) and alteration of the structure of pharyngeal chondrocytes were observed in the morphants as well.

Oculo-auriculo-vertebral spectrum: new genes and literature review on a complex disease

“…A heterozygous missense variant was identified by WES analysis in VWA1 gene (c.905G>A, p.Arg302Gln), in a family in which an autosomal dominant form of HFM associated with unilateral or bilateral microtia segregates in five generations 58. Of note, microduplications of VWA1 and PYGO2 were characterised in a patient presenting with mandibulofacial dysostosis and microtia 59 .…”

“…VWA1 codes for Von Willebrand factor A domain-containing protein 1 and is associated with an autosomal-recessive neuropathy with myopathic features [MIM:619 216]. The knockdown and knockout of its zebrafish homologue support the involvement of this gene in craniofacial cartilages development, possibly through decrease of cranial neural crest cells proliferation 58…”

“…Several zebrafish models were obtained through transient knockdown of gene expression for homologue genes of OAVS. In this way, myt1a ,52 zyg11 ,55 eya3 56 and vwa1 58 knockdown zebrafish models are described in the literature (table 4). In these models, common specific craniofacial features are retrieved in craniofacial cartilage architecture.…”

A narrative review of craniofacial deformities

“…Gorlin and Pindborg first introduced the term HFM in 1964 (63). HFM is a congenital disorder caused by developmental disorders of the first and second pharyngeal arches that mainly affect the jaws, ears, facial soft tissue, orbits, and facial nerve function (64). HFM is the second most common congenital disorder of the face following CL and palate: the incidence is estimated to be in 1:3,000 to 1:5,000 live births.…”

OTX2duplications: a recurrent cause of oculo-auriculo-vertebral spectrum

“…Recently, Timberlake et al reported SF3B2 as the most frequent gene involved in OAVS 16. Before Timberlake et al , various publications also reported five other genes in OAVS individuals: ZYG11B ,17 EYA3 ,18 VWA1 ,19 ZIC3 20 and AMIGO2 21. A large set of copy number variations (CNVs) has also been reported in the literature in patients with OAVS 4 22.…”