@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} } @article {79, title = {DVL3 Alleles Resulting in a -1 Frameshift of the Last Exon Mediate Autosomal-Dominant Robinow Syndrome.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 Mar 03}, pages = {553-561}, abstract = {

Robinow syndrome is a rare congenital disorder characterized by mesomelic limb shortening, genital hypoplasia, and distinctive facial features. Recent reports have identified, in individuals with dominant Robinow syndrome, a specific type of variant characterized by being uniformly located in the penultimate exon of DVL1 and resulting in a -1 frameshift allele with a premature termination codon that escapes nonsense-mediated decay. Here, we studied a cohort of individuals who had been clinically diagnosed with Robinow syndrome but who had not received a molecular diagnosis from variant studies of DVL1, WNT5A, and ROR2. Because of the uniform location of frameshift variants in DVL1-mediated Robinow syndrome and the functional redundancy of DVL1, DVL2, and DVL3, we elected to pursue direct Sanger sequencing of the penultimate exon of DVL1 and its paralogs DVL2 and DVL3 to search for potential disease-associated variants. Remarkably, targeted sequencing identified five unrelated individuals harboring heterozygous, de novo frameshift variants in DVL3, including two splice acceptor mutations and three 1 bp deletions. Similar to the variants observed in DVL1-mediated Robinow syndrome, all variants in DVL3 result in a -1 frameshift, indicating that these highly specific alterations might be a common cause of dominant Robinow syndrome. Here, we review the current knowledge of these peculiar variant alleles in DVL1- and DVL3-mediated Robinow syndrome and further elucidate the phenotypic features present in subjects with DVL1 and DVL3 frameshift mutations.

}, keywords = {Adaptor Proteins, Signal Transducing, Alleles, Base Sequence, Codon, Nonsense, Craniofacial Abnormalities, Dishevelled Proteins, Dwarfism, Exons, Female, Frameshift Mutation, Genetic Variation, Humans, Limb Deformities, Congenital, Male, Molecular Sequence Data, Phosphoproteins, Proto-Oncogene Proteins, Receptor Tyrosine Kinase-like Orphan Receptors, Sequence Analysis, DNA, Sequence Deletion, Urogenital Abnormalities, Wnt Proteins, Wnt-5a Protein}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.01.005}, author = {White, Janson J and Mazzeu, Juliana F and Hoischen, Alexander and Bayram, Yavuz and Withers, Marjorie and Gezdirici, Alper and Kimonis, Virginia and Steehouwer, Marloes and Jhangiani, Shalini N and Muzny, Donna M and Gibbs, Richard A and van Bon, Bregje W M and Sutton, V Reid and Lupski, James R and Brunner, Han G and Carvalho, Claudia M B} }