WNT Signaling Perturbations Underlie the Genetic Heterogeneity of Robinow Syndrome.

TitleWNT Signaling Perturbations Underlie the Genetic Heterogeneity of Robinow Syndrome.
Publication TypeJournal Article
Year of Publication2018
AuthorsWhite, JJ, Mazzeu, JF, Coban-Akdemir, Z, Bayram, Y, Bahrambeigi, V, Hoischen, A, van Bon, BWM, Gezdirici, A, Gulec, EYilmaz, Ramond, F, Touraine, R, Thevenon, J, Shinawi, M, Beaver, E, Heeley, J, Hoover-Fong, J, Durmaz, CD, Karabulut, HGurhan, Marzioglu-Ozdemir, E, Cayir, A, Duz, MB, Seven, M, Price, S, Ferreira, BMerfort, Vianna-Morgante, AM, Ellard, S, Parrish, A, Stals, K, Flores-Daboub, J, Jhangiani, SN, Gibbs, RA, Brunner, HG, V Sutton, R, Lupski, JR, Carvalho, CMB
Corporate AuthorsBaylor-Hopkins Center for Mendelian Genomics
JournalAm J Hum Genet
Date Published2018 Jan 04
KeywordsAdolescent, Adult, Base Sequence, Child, Child, Preschool, Chromosome Segregation, Craniofacial Abnormalities, Diagnosis, Differential, Dwarfism, Female, Genes, Dominant, Genetic Association Studies, Genetic Heterogeneity, Humans, Limb Deformities, Congenital, Male, Middle Aged, Mutation, Missense, Phenotype, Urogenital Abnormalities, Wnt Signaling Pathway

Locus heterogeneity characterizes a variety of skeletal dysplasias often due to interacting or overlapping signaling pathways. Robinow syndrome is a skeletal disorder historically refractory to molecular diagnosis, potentially stemming from substantial genetic heterogeneity. All current known pathogenic variants reside in genes within the noncanonical Wnt signaling pathway including ROR2, WNT5A, and more recently, DVL1 and DVL3. However, ∼70% of autosomal-dominant Robinow syndrome cases remain molecularly unsolved. To investigate this missing heritability, we recruited 21 families with at least one family member clinically diagnosed with Robinow or Robinow-like phenotypes and performed genetic and genomic studies. In total, four families with variants in FZD2 were identified as well as three individuals from two families with biallelic variants in NXN that co-segregate with the phenotype. Importantly, both FZD2 and NXN are relevant protein partners in the WNT5A interactome, supporting their role in skeletal development. In addition to confirming that clustered -1 frameshifting variants in DVL1 and DVL3 are the main contributors to dominant Robinow syndrome, we also found likely pathogenic variants in candidate genes GPC4 and RAC3, both linked to the Wnt signaling pathway. These data support an initial hypothesis that Robinow syndrome results from perturbation of the Wnt/PCP pathway, suggest specific relevant domains of the proteins involved, and reveal key contributors in this signaling cascade during human embryonic development. Contrary to the view that non-allelic genetic heterogeneity hampers gene discovery, this study demonstrates the utility of rare disease genomic studies to parse gene function in human developmental pathways.

Alternate JournalAm J Hum Genet
PubMed ID29276006
PubMed Central IDPMC5777383
Grant ListT32 GM008307 / GM / NIGMS NIH HHS / United States
UM1 HG006542 / HG / NHGRI NIH HHS / United States

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