Browsing by Author "Grange, Dorothy K."

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    Enhanced MAPK1 Function Causes a Neurodevelopmental Disorder within the RASopathy Clinical Spectrum
    (Elsevier, 2020-09-03) Motta, Marialetizia; Pannone, Luca; Pantaleoni, Francesca; Bocchinfuso, Gianfranco; Radio, Francesca Clementina; Cecchetti, Serena; Ciolfi, Andrea; Di Rocco, Martina; Elting, Mariet W.; Brilstra, Eva H.; Boni, Stefania; Mazzanti, Laura; Tamburrino, Federica; Walsh, Larry; Payne, Katelyn; Fernández-Jaén, Alberto; Ganapathi, Mythily; Chung, Wendy K.; Grange, Dorothy K.; Dave-Wala, Ashita; Reshmi, Shalini C.; Bartholomew, Dennis W.; Mouhlas, Danielle; Carpentieri, Giovanna; Bruselles, Alessandro; Pizzi, Simone; Bellacchio, Emanuele; Piceci-Sparascio, Francesca; Lißewski, Christina; Brinkmann, Julia; Waclaw, Ronald R.; Waisfisz, Quinten; van Gassen, Koen; Wentzensen, Ingrid M.; Morrow, Michelle M.; Álvarez, Sara; Martínez-García, Mónica; De Luca, Alessandro; Memo, Luigi; Zampino, Giuseppe; Rossi, Cesare; Seri, Marco; Gelb, Bruce D.; Zenker, Martin; Dallapiccola, Bruno; Stella, Lorenzo; Prada, Carlos E.; Martinelli, Simone; Flex, Elisabetta; Tartaglia, Marco; Medical and Molecular Genetics, School of Medicine
    Signal transduction through the RAF-MEK-ERK pathway, the first described mitogen-associated protein kinase (MAPK) cascade, mediates multiple cellular processes and participates in early and late developmental programs. Aberrant signaling through this cascade contributes to oncogenesis and underlies the RASopathies, a family of cancer-prone disorders. Here, we report that de novo missense variants in MAPK1, encoding the mitogen-activated protein kinase 1 (i.e., extracellular signal-regulated protein kinase 2, ERK2), cause a neurodevelopmental disease within the RASopathy phenotypic spectrum, reminiscent of Noonan syndrome in some subjects. Pathogenic variants promote increased phosphorylation of the kinase, which enhances translocation to the nucleus and boosts MAPK signaling in vitro and in vivo. Two variant classes are identified, one of which directly disrupts binding to MKP3, a dual-specificity protein phosphatase negatively regulating ERK function. Importantly, signal dysregulation driven by pathogenic MAPK1 variants is stimulus reliant and retains dependence on MEK activity. Our data support a model in which the identified pathogenic variants operate with counteracting effects on MAPK1 function by differentially impacting the ability of the kinase to interact with regulators and substrates, which likely explains the minor role of these variants as driver events contributing to oncogenesis. After nearly 20 years from the discovery of the first gene implicated in Noonan syndrome, PTPN11, the last tier of the MAPK cascade joins the group of genes mutated in RASopathies.
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    Loss-of-Function Variants in PPP1R12A: From Isolated Sex Reversal to Holoprosencephaly Spectrum and Urogenital Malformations
    (Elsevier, 2020-01-12) Hughes, Joel J.; Alkhunaizi, Ebba; Kruszka, Paul; Pyle, Louise C.; Grange, Dorothy K.; Berger, Seth I.; Payne, Katelyn K.; Masser-Frye, Diane; Hu, Tommy; Christie, Michelle R.; Clegg, Nancy J.; Everson, Joshua L.; Martinez, Ariel F.; Walsh, Laurence E.; Bedoukian, Emma; Jones, Marilyn C.; Harris, Catharine Jean; Riedhammer, Korbinian M.; Choukair, Daniela; Fechner, Patricia Y.; Rutter, Meilan M.; Hufnagel, Sophia B.; Roifman, Maian; Kletter, Gad B.; Delot, Emmanuele; Vilain, Eric; Lipinski, Robert J.; Vezina, Chad M.; Muenke, Maximilian; Chitayat, David; Pediatrics, School of Medicine
    In two independent ongoing next-generation sequencing projects for individuals with holoprosencephaly and individuals with disorders of sex development, and through international research collaboration, we identified twelve individuals with de novo loss-of-function (LoF) variants in protein phosphatase 1, regulatory subunit 12a (PPP1R12A), an important developmental gene involved in cell migration, adhesion, and morphogenesis. This gene has not been previously reported in association with human disease, and it has intolerance to LoF as illustrated by a very low observed-to-expected ratio of LoF variants in gnomAD. Of the twelve individuals, midline brain malformations were found in five, urogenital anomalies in nine, and a combination of both phenotypes in two. Other congenital anomalies identified included omphalocele, jejunal, and ileal atresia with aberrant mesenteric blood supply, and syndactyly. Six individuals had stop gain variants, five had a deletion or duplication resulting in a frameshift, and one had a canonical splice acceptor site loss. Murine and human in situ hybridization and immunostaining revealed PPP1R12A expression in the prosencephalic neural folds and protein localization in the lower urinary tract at critical periods for forebrain division and urogenital development. Based on these clinical and molecular findings, we propose the association of PPP1R12A pathogenic variants with a congenital malformations syndrome affecting the embryogenesis of the brain and genitourinary systems and including disorders of sex development.