Abnormal WNT5A Signaling Causes Mandibular Hypoplasia in Robinow Syndrome

Abstract

The study of rare genetic diseases provides valuable insights into human gene function. Here, we investigate dominant Robinow syndrome (RS), which affects the WNT5A signaling pathway. Autosomal dominant RS is caused by missense mutations in WNT5A or nonsense mutations in the adaptor protein DVL1 or DVL3. The recessive form of the disease is caused by loss-of-function mutations in the receptor ROR2. RS is characterized by hypertelorism, midface, and mandibular hypoplasia. Here, we focus on the missense mutations in WNT5A, since the impact on function is difficult to predict from in silico analysis. We used chicken embryo to express wild-type or 2 mutant versions of human WNT5A in the mandible and then examined the morphologic, cellular, and molecular effects. The 3 experimental viruses-wt WNT5A, WNT5A, or WNT5A-all caused shortening of the mandible on the injected side as compared with GFP controls. Although the phenotypes initially appeared similar, we uncovered specific disruption of chondrocyte polarity and shape, inhibition of cell migration, differences in target gene expression, and absence of JNK signaling only in the presence of mutant viruses. In addition, the missense mutations do not appear to block receptor binding, since in paracrine experiments, the mutant protein inhibits cell migration. In this study, we ruled out a straightforward gain or loss of function caused by the WNT5A missense mutations. Instead, the mutations are likely redirecting WNT signaling away from JNK-PCP toward other noncanonical pathways. We conclude that in RS, WNT5A missense mutations have dominant neomorphic effects that interfere with the function of the wild-type protein.

A systematic genetic analysis and visualization of phenotypic heterogeneity among orofacial cleft GWAS signals

“…The 5q35.2 signal is adjacent to MSX2, a gene critical for human skull development and associated with craniosynostosis, parietal foramina, and orofacial clefting (Wilkie et al, 2000). Finally, the 3p14.3 locus had two independent signals within the same topologically-associated domain containing WNT5A, a gene in which mutations can cause mandibular hypoplasia in Robinow syndrome (Hosseini-Farahabadi et al, 2017;Person et al, 2010) and ERC2, encoding a synapse protein (Ohtsuka et al, 2002). As WNT5A is a stronger candidate gene for OFCs than ERC2, we represent the two signals as WNT5A "a" and WNT5A "b".…”

Craniofacial development: discoveries made in the chicken embryo

“…The virus is avian-specific and permits local misexpression in regions of the face while allowing normal development in the rest of the embryo. Viruses may be utilized to introduce an exogenous gene , Eames et al, 2004, Foppiano et al, 2007, Hu et al, 2008, mutant versions of a gene (Hosseini-Farahabadi et al, 2017) or less commonly, to knock down a gene using an shRNA cassette (Bond et al, 2016). Moreover, since conservation of protein sequence is very high in developmental genes, the exogenous gene used for overexpression may be from the chicken or another species.…”

“…The advantage of using sequence from another species is that the level of exogenous gene expression can be subsequently measured against the backdrop of endogenous target gene changes from the chicken. We have previously quantified the levels of expression from RCAS viruses (Geetha-Loganathan et al, 2014, Hosseini-Farahabadi et al, 2017, Nimmagadda et al, 2015 and measured gradual increases in expression between 48 and 96h. Interestingly, the overexpression of genes can be used to detect target genes and importantly, to exclude those that are not likely to be involved in a particular pathway.…”

“…Through a series of in vivo and in vitro experiments, we showed that WNT5A represses canonical WNT signaling on order to allow for the differentiation of craniofacial cartilage. In a recent study, the overexpression of WNT5A in vivo was characterized in more detail and compared to mutant version of the gene that causes Robinow syndrome (Hosseini-Farahabadi et al, 2017). Patients with a single allele containing the WNT5A variants have major craniofacial and limb anomalies (Person et al, 2010, Roifman et al, 2014.…”

Principales entidades genéticas asociadas con dientes supernumerarios

“…61 Además, también es causado por mutaciones sin sentido en el gen DVL1 (OMIM 601365) y en el gen DVL3 (OMIM 601368) del extremo C de la proteína adaptadora Dishevelled. 62 Esta entidad también se presenta con un patrón autosómico recesivo (OMIM 268310). 59,60 Su prevalencia es de 1 en 500 000 nacidos vivos.…”