@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 {361, title = {Dual molecular diagnosis contributes to atypical Prader-Willi phenotype in monozygotic twins.}, journal = {Am J Med Genet A}, volume = {173}, year = {2017}, month = {2017 Sep}, pages = {2451-2455}, abstract = {

We describe monozygotic twin girls with genetic variation at two separate loci resulting in a blended phenotype of Prader-Willi syndrome and Pitt-Hopkins syndrome. These girls were diagnosed in early infancy with Prader-Willi syndrome, but developed an atypical phenotype, with apparent intellectual deficiency and lack of obesity. Array-comparative genomic hybridization confirmed a de novo paternal deletion of the 15q11.2q13 region and exome sequencing identified a second mutational event in both girls, which was a novel variant c.145+1G>A affecting a TCF4 canonical splicing site inherited from the mosaic mother. RNA studies showed that the variant abolished the donor splicing site, which was accompanied by activation of an alternative non-canonical splicing-site which then predicts a premature stop codon in the following exon. Clinical re-evaluation of the twins indicated that both variants are likely contributing to the more severe phenotypic presentation. Our data show that atypical clinical presentations may actually be the expression of blended clinical phenotypes arising from independent pathogenic events at two loci.

}, keywords = {Adolescent, Base Sequence, Child, Chromosome Deletion, Chromosomes, Human, Pair 15, Comparative Genomic Hybridization, Exome, Facies, Female, Humans, Hyperventilation, Intellectual Disability, Obesity, Pathology, Molecular, Phenotype, Prader-Willi Syndrome, Transcription Factor 4, Twins, Monozygotic}, issn = {1552-4833}, doi = {10.1002/ajmg.a.38315}, author = {Jehee, Fernanda S and de Oliveira, Valdirene T and Gurgel-Giannetti, Juliana and Pietra, Rafaella X and Rubatino, Fernando V M and Carobin, Nat{\'a}lia V and Vianna, Gabrielle S and de Freitas, Mariana L and Fernandes, Karla S and Ribeiro, Beatriz S V and Br{\"u}ggenwirth, Hennie T and Ali-Amin, Roza and White, Janson J and Akdemir, Zeynep C and Jhangiani, Shalini N and Gibbs, Richard A and Lupski, James R and Varela, Monica C and Koiffmann, C{\'e}lia and Rosenberg, Carla and Carvalho, Claudia M B} } @article {414, title = {De novo missense variants in PPP1CB are associated with intellectual disability and congenital heart disease.}, journal = {Hum Genet}, volume = {135}, year = {2016}, month = {2016 12}, pages = {1399-1409}, abstract = {

Intellectual disabilities are genetically heterogeneous and can be associated with congenital anomalies. Using whole-exome sequencing (WES), we identified five different de novo missense variants in the protein phosphatase-1 catalytic subunit beta (PPP1CB) gene in eight unrelated individuals who share an overlapping phenotype of dysmorphic features, macrocephaly, developmental delay or intellectual disability (ID), congenital heart disease, short stature, and skeletal and connective tissue abnormalities. Protein phosphatase-1 (PP1) is a serine/threonine-specific protein phosphatase involved in the dephosphorylation of a variety of proteins. The PPP1CB gene encodes a PP1 subunit that regulates the level of protein phosphorylation. All five altered amino acids we observed are highly conserved among the PP1 subunit family, and all are predicted to disrupt PP1 subunit binding and impair dephosphorylation. Our data suggest that our heterozygous de novo PPP1CB pathogenic variants are associated with syndromic intellectual disability.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Exome, Female, Genetic Association Studies, Genetic Predisposition to Disease, Heart Defects, Congenital, Humans, Intellectual Disability, Male, Mutation, Missense, Phosphorylation, Protein Phosphatase 1}, issn = {1432-1203}, doi = {10.1007/s00439-016-1731-1}, author = {Ma, Lijiang and Bayram, Yavuz and McLaughlin, Heather M and Cho, Megan T and Krokosky, Alyson and Turner, Clesson E and Lindstrom, Kristin and Bupp, Caleb P and Mayberry, Katey and Mu, Weiyi and Bodurtha, Joann and Weinstein, Veronique and Zadeh, Neda and Alcaraz, Wendy and Powis, Z{\"o}e and Shao, Yunru and Scott, Daryl A and Lewis, Andrea M and White, Janson J and Jhangiani, Shalani N and Gulec, Elif Yilmaz and Lalani, Seema R and Lupski, James R and Retterer, Kyle and Schnur, Rhonda E and Wentzensen, Ingrid M and Bale, Sherri and Chung, Wendy K} }