@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 {9, title = {Identification of a RAI1-associated disease network through integration of exome sequencing, transcriptomics, and 3D genomics.}, journal = {Genome Med}, volume = {8}, year = {2016}, month = {2016 Nov 01}, pages = {105}, abstract = {

BACKGROUND: Smith-Magenis syndrome (SMS) is a developmental disability/multiple congenital anomaly disorder resulting from haploinsufficiency of RAI1. It is characterized by distinctive facial features, brachydactyly, sleep disturbances, and stereotypic behaviors.

METHODS: We investigated a cohort of 15 individuals with a clinical suspicion of SMS who showed neither deletion in the SMS critical region nor damaging variants in RAI1 using whole exome sequencing. A combination of network analysis (co-expression and biomedical text mining), transcriptomics, and circularized chromatin conformation capture (4C-seq) was applied to verify whether modified genes are part of the same disease network as known SMS-causing genes.

RESULTS: Potentially deleterious variants were identified in nine of these individuals using whole-exome sequencing. Eight of these changes affect KMT2D, ZEB2, MAP2K2, GLDC, CASK, MECP2, KDM5C, and POGZ, known to be associated with Kabuki syndrome 1, Mowat-Wilson syndrome, cardiofaciocutaneous syndrome, glycine encephalopathy, mental retardation and microcephaly with pontine and cerebellar hypoplasia, X-linked mental retardation 13, X-linked mental retardation Claes-Jensen type, and White-Sutton syndrome, respectively. The ninth individual carries a de novo variant in JAKMIP1, a regulator of neuronal translation that was recently found deleted in a patient with autism spectrum disorder. Analyses of co-expression and biomedical text mining suggest that these pathologies and SMS are part of the same disease network. Further support for this hypothesis was obtained from transcriptome profiling that showed that the expression levels of both Zeb2 and Map2k2 are perturbed in Rai1 mice. As an orthogonal approach to potentially contributory disease gene variants, we used chromatin conformation capture to reveal chromatin contacts between RAI1 and the loci flanking ZEB2 and GLDC, as well as between RAI1 and human orthologs of the genes that show perturbed expression in our Rai1 mouse model.

CONCLUSIONS: These holistic studies of RAI1 and its interactions allow insights into SMS and other disorders associated with intellectual disability and behavioral abnormalities. Our findings support a pan-genomic approach to the molecular diagnosis of a distinctive disorder.

}, keywords = {Animals, Embryo, Mammalian, Exome, Female, Gene Regulatory Networks, Genomics, Humans, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Mutation, Phenotype, Real-Time Polymerase Chain Reaction, Reverse Transcriptase Polymerase Chain Reaction, RNA, Messenger, Smith-Magenis Syndrome, Trans-Activators, Transcription Factors, Transcriptome}, issn = {1756-994X}, doi = {10.1186/s13073-016-0359-z}, author = {Loviglio, Maria Nicla and Beck, Christine R and White, Janson J and Leleu, Marion and Harel, Tamar and Guex, Nicolas and Niknejad, Anne and Bi, Weimin and Chen, Edward S and Crespo, Isaac and Yan, Jiong and Charng, Wu-Lin and Gu, Shen and Fang, Ping and Coban-Akdemir, Zeynep and Shaw, Chad A and Jhangiani, Shalini N and Muzny, Donna M and Gibbs, Richard A and Rougemont, Jacques and Xenarios, Ioannis and Lupski, James R and Reymond, Alexandre} }