@article {446, title = {WNT Signaling Perturbations Underlie the Genetic Heterogeneity of Robinow Syndrome.}, journal = {Am J Hum Genet}, volume = {102}, year = {2018}, month = {2018 01 04}, pages = {27-43}, abstract = {

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.

}, keywords = {Adolescent, 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}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2017.10.002}, author = {White, Janson J and Mazzeu, Juliana F and Coban-Akdemir, Zeynep and Bayram, Yavuz and Bahrambeigi, Vahid and Hoischen, Alexander and van Bon, Bregje W M and Gezdirici, Alper and Gulec, Elif Yilmaz and Ramond, Francis and Touraine, Renaud and Thevenon, Julien and Shinawi, Marwan and Beaver, Erin and Heeley, Jennifer and Hoover-Fong, Julie and Durmaz, Ceren D and Karabulut, Halil Gurhan and Marzioglu-Ozdemir, Ebru and Cayir, Atilla and Duz, Mehmet B and Seven, Mehmet and Price, Susan and Ferreira, Barbara Merfort and Vianna-Morgante, Angela M and Ellard, Sian and Parrish, Andrew and Stals, Karen and Flores-Daboub, Josue and Jhangiani, Shalini N and Gibbs, Richard A and Brunner, Han G and Sutton, V Reid and Lupski, James R and Carvalho, Claudia M B} } @article {12, title = {Novel mutations in LRP6 highlight the role of WNT signaling in tooth agenesis.}, journal = {Genet Med}, volume = {18}, year = {2016}, month = {2016 11}, pages = {1158-1162}, abstract = {

PURPOSE: We aimed to identify a novel genetic cause of tooth agenesis (TA) and/or orofacial clefting (OFC) by combining whole-exome sequencing (WES) and targeted resequencing in a large cohort of TA and OFC patients.

METHODS: WES was performed in two unrelated patients: one with severe TA and OFC and another with severe TA only. After deleterious mutations were identified in a gene encoding low-density lipoprotein receptor-related protein 6 (LRP6), all its exons were resequenced with molecular inversion probes in 67 patients with TA, 1,072 patients with OFC, and 706 controls.

RESULTS: We identified a frameshift (c.4594delG, p.Cys1532fs) and a canonical splice-site mutation (c.3398-2A>C, p.?) in LRP6, respectively, in the patient with TA and OFC and in the patient with severe TA only. The targeted resequencing showed significant enrichment of unique LRP6 variants in TA patients but not in nonsyndromic OFC patients. Of the five variants in patients with TA, two affected the canonical splice site and three were missense variants; all variants segregated with the dominant phenotype, and in one case the missense mutation occurred de novo.

CONCLUSION: Mutations in LRP6 cause TA in humans.Genet Med 18 11, 1158-1162.

}, keywords = {Adolescent, Anodontia, Child, Exome, Female, Frameshift Mutation, Genetic Predisposition to Disease, Humans, Low Density Lipoprotein Receptor-Related Protein-6, Male, Mutation, Missense, Pedigree, Sequence Analysis, DNA, Wnt Signaling Pathway}, issn = {1530-0366}, doi = {10.1038/gim.2016.10}, author = {Ockeloen, Charlotte W and Khandelwal, Kriti D and Dreesen, Karoline and Ludwig, Kerstin U and Sullivan, Robert and van Rooij, Iris A L M and Thonissen, Michelle and Swinnen, Steven and Phan, Milien and Conte, Federica and Ishorst, Nina and Gilissen, Christian and RoaFuentes, Laury and van de Vorst, Maartje and Henkes, Arjen and Steehouwer, Marloes and van Beusekom, Ellen and Bloemen, Marjon and Vankeirsbilck, Bruno and Berg{\'e}, Stefaan and Hens, Greet and Schoenaers, Joseph and Poorten, Vincent Vander and Roosenboom, Jasmien and Verdonck, An and Devriendt, Koen and Roeleveldt, Nel and Jhangiani, Shalini N and Vissers, Lisenka E L M and Lupski, James R and de Ligt, Joep and Von den Hoff, Johannes W and Pfundt, Rolph and Brunner, Han G and Zhou, Huiqing and Dixon, Jill and Mangold, Elisabeth and van Bokhoven, Hans and Dixon, Michael J and Kleefstra, Tjitske and Hoischen, Alexander and Carels, Carine E L} }