@article {424, title = {De Novo Missense Mutations in DHX30 Impair Global Translation and Cause a Neurodevelopmental Disorder.}, journal = {Am J Hum Genet}, volume = {101}, year = {2017}, month = {2017 Nov 02}, pages = {716-724}, abstract = {

DHX30 is a member of the family of DExH-box helicases, which use ATP hydrolysis to unwind RNA secondary structures. Here we identified six different de novo missense mutations in DHX30 in twelve unrelated individuals affected by global developmental delay (GDD), intellectual disability (ID), severe speech impairment and gait abnormalities. While four mutations are recurrent, two are unique with one affecting the codon of one recurrent mutation. All amino acid changes are located within highly conserved helicase motifs and were found to either impair ATPase activity or RNA recognition in different in~vitro assays. Moreover, protein variants exhibit an increased propensity to trigger stress granule (SG) formation resulting in global translation inhibition. Thus, our findings highlight the prominent role of translation control in development and function of the central nervous system and also provide molecular insight into how DHX30 dysfunction might cause a neurodevelopmental disorder.

}, keywords = {Adenosine Triphosphatases, Adolescent, Amino Acids, Cell Line, Cell Line, Tumor, Central Nervous System, Child, Child, Preschool, Developmental Disabilities, Female, HEK293 Cells, Humans, Intellectual Disability, Male, Mutation, Missense, RNA, RNA Helicases}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2017.09.014}, author = {Lessel, Davor and Schob, Claudia and K{\"u}ry, S{\'e}bastien and Reijnders, Margot R F and Harel, Tamar and Eldomery, Mohammad K and Coban-Akdemir, Zeynep and Denecke, Jonas and Edvardson, Shimon and Colin, Estelle and Stegmann, Alexander P A and Gerkes, Erica H and Tessarech, Marine and Bonneau, Dominique and Barth, Magalie and Besnard, Thomas and Cogn{\'e}, Benjamin and Revah-Politi, Anya and Strom, Tim M and Rosenfeld, Jill A and Yang, Yaping and Posey, Jennifer E and Immken, LaDonna and Oundjian, Nelly and Helbig, Katherine L and Meeks, Naomi and Zegar, Kelsey and Morton, Jenny and Schieving, Jolanda H and Claasen, Ana and Huentelman, Matthew and Narayanan, Vinodh and Ramsey, Keri and Brunner, Han G and Elpeleg, Orly and Mercier, Sandra and B{\'e}zieau, St{\'e}phane and Kubisch, Christian and Kleefstra, Tjitske and Kindler, Stefan and Lupski, James R and Kreienkamp, Hans-J{\"u}rgen} } @article {74, title = {Mosaic Activating Mutations in FGFR1 Cause Encephalocraniocutaneous Lipomatosis.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 Mar 03}, pages = {579-587}, abstract = {

Encephalocraniocutaneous lipomatosis (ECCL) is a sporadic condition characterized by ocular, cutaneous, and central nervous system anomalies. Key clinical features include a well-demarcated hairless fatty nevus on the scalp, benign ocular tumors, and central nervous system lipomas. Seizures, spasticity, and intellectual disability can be present, although affected individuals without seizures and with normal intellect have also been reported. Given the patchy and asymmetric nature of the malformations, ECCL has been hypothesized to be due to a post-zygotic, mosaic mutation. Despite phenotypic overlap with several other disorders associated with mutations in the RAS-MAPK and PI3K-AKT pathways, the molecular etiology of ECCL remains unknown. Using exome sequencing of DNA from multiple affected tissues from five unrelated individuals with ECCL, we identified two mosaic mutations, c.1638C>A (p.Asn546Lys) and c.1966A>G (p.Lys656Glu) within the tyrosine kinase domain of FGFR1, in two affected individuals each. These two residues are the most commonly mutated residues in FGFR1 in human cancers and are associated primarily with CNS tumors. Targeted resequencing of FGFR1 in multiple tissues from an independent cohort of individuals with ECCL identified one additional individual with a c.1638C>A (p.Asn546Lys) mutation in FGFR1. Functional studies of ECCL fibroblast cell lines show increased levels of phosphorylated FGFRs and phosphorylated FRS2, a direct substrate of FGFR1, as well as constitutive activation of RAS-MAPK signaling. In addition to identifying the molecular etiology of ECCL, our results support the emerging overlap between mosaic developmental disorders and tumorigenesis.

}, keywords = {Adolescent, Cell Line, Tumor, Central Nervous System Neoplasms, Child, Preschool, Exome, Eye, Eye Diseases, Female, Humans, Infant, Lipomatosis, Male, Mutation, Mutation, Missense, Neurocutaneous Syndromes, Phosphatidylinositol 3-Kinases, Proto-Oncogene Proteins c-akt, Receptor, Fibroblast Growth Factor, Type 1, Seizures, Sequence Analysis, DNA}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.02.006}, author = {Bennett, James T and Tan, Tiong Yang and Alcantara, Diana and T{\'e}trault, Martine and Timms, Andrew E and Jensen, Dana and Collins, Sarah and Nowaczyk, Malgorzata J M and Lindhurst, Marjorie J and Christensen, Katherine M and Braddock, Stephen R and Brandling-Bennett, Heather and Hennekam, Raoul C M and Chung, Brian and Lehman, Anna and Su, John and Ng, SuYuen and Amor, David J and Majewski, Jacek and Biesecker, Les G and Boycott, Kym M and Dobyns, William B and O{\textquoteright}Driscoll, Mark and Moog, Ute and McDonell, Laura M} } @article {184, title = {Cerebral visual impairment and intellectual disability caused by PGAP1 variants.}, journal = {Eur J Hum Genet}, volume = {23}, year = {2015}, month = {2015 Dec}, pages = {1689-93}, abstract = {

Homozygous variants in PGAP1 (post-GPI attachment to proteins 1) have recently been identified in two families with developmental delay, seizures and/or spasticity. PGAP1 is a member of the glycosylphosphatidylinositol anchor biosynthesis and remodeling pathway and defects in this pathway are a subclass of congenital disorders of glycosylation. Here we performed whole-exome sequencing in an individual with cerebral visual impairment (CVI), intellectual disability (ID), and factor XII deficiency and revealed compound heterozygous variants in PGAP1, c.274_276del (p.(Pro92del)) and c.921_925del (p.(Lys308Asnfs*25)). Subsequently, PGAP1-deficient Chinese hamster ovary (CHO)-cell lines were transfected with either mutant or wild-type constructs and their sensitivity to phosphatidylinositol-specific phospholipase C (PI-PLC) treatment was measured. The mutant constructs could not rescue the PGAP1-deficient CHO cell lines resistance to PI-PLC treatment. In addition, lymphoblastoid cell lines (LCLs) of the affected individual showed no sensitivity to PI-PLC treatment, whereas the LCLs of the heterozygous carrier parents were partially resistant. In conclusion, we report novel PGAP1 variants in a boy with CVI and ID and a proven functional loss of PGAP1 and show, to our knowledge, for the first time this genetic association with CVI.

}, keywords = {Animals, Cell Line, Tumor, Child, CHO Cells, Cricetinae, Cricetulus, Humans, Intellectual Disability, Male, Membrane Proteins, Mutation, Phosphoinositide Phospholipase C, Phosphoric Monoester Hydrolases, Syndrome, Vision Disorders, Visual Perception}, issn = {1476-5438}, doi = {10.1038/ejhg.2015.42}, author = {Bosch, Dani{\"e}lle G M and Boonstra, F Nienke and Kinoshita, Taroh and Jhangiani, Shalini and de Ligt, Joep and Cremers, Frans P M and Lupski, James R and Murakami, Yoshiko and de Vries, Bert B A} } @article {187, title = {Frequent somatic reversion of KRT1 mutations in ichthyosis with confetti.}, journal = {J Clin Invest}, volume = {125}, year = {2015}, month = {2015 Apr}, pages = {1703-7}, abstract = {

Widespread reversion of genetic disease is rare; however, such events are particularly evident in some skin disorders in which normal clones develop on a background of affected skin. We previously demonstrated that mutations in keratin 10 (KRT10) cause ichthyosis with confetti (IWC), a severe dominant disorder that is characterized by progressive development of hundreds of normal skin spots via revertant mosaicism. Here, we report on a clinical and histological IWC subtype in which affected subjects have red, scaly skin at birth, experience worsening palmoplantar keratoderma in childhood, and develop hundreds of normal skin spots, beginning at around 20 years of age, that increase in size and number over time. We identified a causal de novo mutation in keratin 1 (KRT1). Similar to IWC-causing KRT10 mutations, this mutation in KRT1 resulted in a C-terminal frameshift, replacing 22 C-terminal amino acids with an alternate 30-residue peptide. Mutant KRT1 caused partial collapse of the cytoplasmic intermediate filament network and mislocalized to the nucleus. As with KRT10 mutations causing IWC, reversion of KRT1 mutations occurred via mitotic recombination. Because reversion is not observed with other disease-causing keratin mutations, the results of this study implicate KRT1 and KRT10 C-terminal frameshift mutations in the high frequency of revertant mosaicism in IWC.

}, keywords = {Adult, Age of Onset, Amino Acid Sequence, Cell Line, Tumor, Cell Nucleus, Child, Child, Preschool, Chromosomes, Human, Pair 12, Cytoskeleton, Frameshift Mutation, Humans, Ichthyosis, Intermediate Filaments, Keratin-1, Keratinocytes, Loss of Heterozygosity, Male, Molecular Sequence Data, Mosaicism, Phenotype, Polymorphism, Single Nucleotide, Protein Transport, Transfection}, issn = {1558-8238}, doi = {10.1172/JCI64415}, author = {Choate, Keith A and Lu, Yin and Zhou, Jing and Elias, Peter M and Zaidi, Samir and Paller, Amy S and Farhi, Anita and Nelson-Williams, Carol and Crumrine, Debra and Milstone, Leonard M and Lifton, Richard P} }