@article {491, title = {Dual Molecular Effects of Dominant RORA Mutations Cause Two Variants of Syndromic Intellectual Disability with Either Autism or Cerebellar Ataxia.}, journal = {Am J Hum Genet}, volume = {102}, year = {2018}, month = {2018 05 03}, pages = {744-759}, abstract = {

RORĪ±, the RAR-related orphan nuclear receptor alpha, is essential for cerebellar development. The spontaneous mutant mouse staggerer, with an ataxic gait caused by neurodegeneration of cerebellar Purkinje cells, was discovered two decades ago to result from homozygous intragenic Rora deletions. However, RORA mutations were hitherto undocumented in humans. Through a multi-centric collaboration, we identified three copy-number variant deletions (two de novo and one dominantly inherited in three generations), one de novo disrupting duplication, and nine de novo point mutations (three truncating, one canonical splice site, and five missense mutations) involving RORA in 16 individuals from 13 families with variable neurodevelopmental delay and intellectual disability (ID)-associated autistic features, cerebellar ataxia, and epilepsy. Consistent with the human and mouse data, disruption of the D.~rerio ortholog, roraa, causes significant reduction in the size of the developing cerebellum. Systematic in~vivo complementation studies showed that, whereas wild-type human RORA mRNA could complement the cerebellar pathology, missense variants had two distinct pathogenic mechanisms of either haploinsufficiency or a dominant toxic effect according to their localization in the ligand-binding or DNA-binding domains, respectively. This dichotomous direction of effect is likely relevant to the phenotype in humans: individuals with loss-of-function variants leading to haploinsufficiency show ID with autistic features, while individuals with de novo dominant toxic variants present with ID, ataxia, and cerebellar atrophy. Our combined genetic and functional data highlight the complex mutational landscape at the human RORA locus and suggest that dual mutational effects likely determine phenotypic outcome.

}, keywords = {Adolescent, Adult, Aged, 80 and over, Alleles, Animals, Autistic Disorder, Brain, Cerebellar Ataxia, Child, Child, Preschool, Disease Models, Animal, DNA Copy Number Variations, Female, Genes, Dominant, Genetic Complementation Test, Humans, Intellectual Disability, Larva, Magnetic Resonance Imaging, Male, Middle Aged, Mutation, Missense, Nuclear Receptor Subfamily 1, Group F, Member 1, Purkinje Cells, Syndrome, Zebrafish}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.02.021}, author = {Guissart, Claire and Latypova, X{\'e}nia and Rollier, Paul and Khan, Tahir N and Stamberger, Hannah and McWalter, Kirsty and Cho, Megan T and Kjaergaard, Susanne and Weckhuysen, Sarah and Lesca, Gaetan and Besnard, Thomas and {\~O}unap, Katrin and Schema, Lynn and Chiocchetti, Andreas G and McDonald, Marie and de Bellescize, Julitta and Vincent, Marie and Van Esch, Hilde and Sattler, Shannon and Forghani, Irman and Thiffault, Isabelle and Freitag, Christine M and Barbouth, Deborah Sara and Cadieux-Dion, Maxime and Willaert, Rebecca and Guillen Sacoto, Maria J and Safina, Nicole P and Dubourg, Christ{\`e}le and Grote, Lauren and Carr{\'e}, Wilfrid and Saunders, Carol and Pajusalu, Sander and Farrow, Emily and Boland, Anne and Karlowicz, Danielle Hays and Deleuze, Jean-Fran{\c c}ois and Wojcik, Monica H and Pressman, Rena and Isidor, Bertrand and Vogels, Annick and Van Paesschen, Wim and Al-Gazali, Lihadh and Al Shamsi, Aisha Mohamed and Claustres, Mireille and Pujol, Aurora and Sanders, Stephan J and Rivier, Fran{\c c}ois and Leboucq, Nicolas and Cogn{\'e}, Benjamin and Sasorith, Souphatta and Sanlaville, Damien and Retterer, Kyle and Odent, Sylvie and Katsanis, Nicholas and B{\'e}zieau, St{\'e}phane and Koenig, Michel and Davis, Erica E and Pasquier, Laurent and K{\"u}ry, S{\'e}bastien} } @article {638, title = {A defect in myoblast fusion underlies Carey-Fineman-Ziter syndrome.}, journal = {Nat Commun}, volume = {8}, year = {2017}, month = {2017 07 06}, pages = {16077}, abstract = {

Multinucleate cellular syncytial formation is a hallmark of skeletal muscle differentiation. Myomaker, encoded by Mymk (Tmem8c), is a well-conserved plasma membrane protein required for myoblast fusion to form multinucleated myotubes in mouse, chick, and zebrafish. Here, we report that autosomal recessive mutations in MYMK (OMIM 615345) cause Carey-Fineman-Ziter syndrome in humans (CFZS; OMIM 254940) by reducing but not eliminating MYMK function. We characterize MYMK-CFZS as a congenital myopathy with marked facial weakness and additional clinical and pathologic features that distinguish it from other congenital neuromuscular syndromes. We show that a heterologous cell fusion assay in vitro and allelic complementation experiments in mymk knockdown and mymk zebrafish in vivo can differentiate between MYMK wild type, hypomorphic and null alleles. Collectively, these data establish that MYMK activity is necessary for normal muscle development and maintenance in humans, and expand the spectrum of congenital myopathies to include cell-cell fusion deficits.

}, keywords = {Adult, Amino Acid Sequence, Animals, Cell Fusion, Child, Disease Models, Animal, Embryo, Nonmammalian, Female, Gene Expression, Genes, Recessive, Genetic Complementation Test, Humans, Infant, Male, Membrane Proteins, Mobius Syndrome, Morphogenesis, Muscle Proteins, Muscle, Skeletal, Muscular Diseases, Mutation, Myoblasts, Pedigree, Pierre Robin Syndrome, Sequence Alignment, Sequence Homology, Amino Acid, Zebrafish, Zebrafish Proteins}, issn = {2041-1723}, doi = {10.1038/ncomms16077}, author = {Di Gioia, Silvio Alessandro and Connors, Samantha and Matsunami, Norisada and Cannavino, Jessica and Rose, Matthew F and Gilette, Nicole M and Artoni, Pietro and de Macena Sobreira, Nara Lygia and Chan, Wai-Man and Webb, Bryn D and Robson, Caroline D and Cheng, Long and Van Ryzin, Carol and Ramirez-Martinez, Andres and Mohassel, Payam and Leppert, Mark and Scholand, Mary Beth and Grunseich, Christopher and Ferreira, Carlos R and Hartman, Tyler and Hayes, Ian M and Morgan, Tim and Markie, David M and Fagiolini, Michela and Swift, Amy and Chines, Peter S and Speck-Martins, Carlos E and Collins, Francis S and Jabs, Ethylin Wang and B{\"o}nnemann, Carsten G and Olson, Eric N and Carey, John C and Robertson, Stephen P and Manoli, Irini and Engle, Elizabeth C} } @article {395, title = {Mutations in KDSR Cause Recessive Progressive Symmetric Erythrokeratoderma.}, journal = {Am J Hum Genet}, volume = {100}, year = {2017}, month = {2017 Jun 01}, pages = {978-984}, abstract = {

The discovery of new genetic determinants of inherited skin disorders has been instrumental to the understanding of epidermal function, differentiation, and renewal. Here, we show that mutations in KDSR (3-ketodihydrosphingosine reductase), encoding an enzyme in the ceramide synthesis pathway, lead to a previously undescribed recessive Mendelian disorder in the progressive symmetric erythrokeratoderma spectrum. This disorder is characterized by severe lesions of thick scaly skin on the face and genitals and thickened, red, and scaly skin on the hands and feet. Although exome sequencing revealed several of the KDSR mutations, we employed genome sequencing to discover a pathogenic 346 kb inversion in multiple probands, and cDNA sequencing and a splicing assay established that two mutations, including a recurrent silent third base change, cause exon skipping. Immunohistochemistry and yeast complementation studies demonstrated that the mutations cause defects in KDSR function. Systemic isotretinoin therapy has achieved nearly complete resolution in the two probands in whom it has been applied, consistent with the effects of retinoic acid on alternative pathways for ceramide generation.

}, keywords = {Alcohol Oxidoreductases, Ceramides, Genes, Recessive, Genetic Complementation Test, Genetic Predisposition to Disease, Heterozygote, Humans, Intermediate Filament Proteins, Keratosis, Mutation, Polymorphism, Single Nucleotide, RNA Splicing, Saccharomyces cerevisiae}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2017.05.003}, author = {Boyden, Lynn M and Vincent, Nicholas G and Zhou, Jing and Hu, Ronghua and Craiglow, Brittany G and Bayliss, Susan J and Rosman, Ilana S and Lucky, Anne W and Diaz, Luis A and Goldsmith, Lowell A and Paller, Amy S and Lifton, Richard P and Baserga, Susan J and Choate, Keith A} } @article {342, title = {MECR Mutations Cause Childhood-Onset Dystonia and Optic Atrophy, a Mitochondrial Fatty Acid Synthesis Disorder.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Dec 01}, pages = {1229-1244}, abstract = {

Mitochondrial fatty acid synthesis (mtFAS) is an evolutionarily conserved pathway essential for the function of the respiratory chain and several mitochondrial enzyme complexes. We report here a unique neurometabolic human disorder caused by defective mtFAS. Seven individuals from five unrelated families presented with childhood-onset dystonia, optic atrophy, and basal ganglia signal abnormalities on MRI. All affected individuals were found to harbor recessive mutations in MECR encoding the mitochondrial trans-2-enoyl-coenzyme A-reductase involved in human mtFAS. All six mutations are extremely rare in the general population, segregate with the disease in the families, and are predicted to be deleterious. The nonsense c.855T>G (p.Tyr285), c.247_250del (p.Asn83Hisfs4), and splice site c.830+2_830+3insT mutations lead to C-terminal truncation variants of MECR. The missense c.695G>A (p.Gly232Glu), c.854A>G (p.Tyr285Cys), and c.772C>T (p.Arg258Trp) mutations involve conserved amino acid residues, are located within the cofactor binding domain, and are predicted by structural analysis to have a destabilizing effect. Yeast modeling and complementation studies validated the pathogenicity of the MECR mutations. Fibroblast cell lines from affected individuals displayed reduced levels of both MECR and lipoylated proteins as well as defective respiration. These results suggest that mutations in MECR cause a distinct human disorder of the mtFAS pathway. The observation of decreased lipoylation raises the possibility of a potential therapeutic strategy.

}, keywords = {Basal Ganglia, Cells, Cultured, Child, Child, Preschool, Dystonic Disorders, Fatty Acids, Female, Fibroblasts, Genetic Complementation Test, Humans, Infant, Male, Mitochondria, Mitochondrial Diseases, Models, Molecular, Mutation, Mutation, Missense, Optic Atrophy, Oxidoreductases Acting on CH-CH Group Donors, Pedigree, RNA Splice Sites, Saccharomyces cerevisiae}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.09.021}, author = {Heimer, Gali and Ker{\"a}t{\"a}r, Juha M and Riley, Lisa G and Balasubramaniam, Shanti and Eyal, Eran and Pietik{\"a}inen, Laura P and Hiltunen, J Kalervo and Marek-Yagel, Dina and Hamada, Jeffrey and Gregory, Allison and Rogers, Caleb and Hogarth, Penelope and Nance, Martha A and Shalva, Nechama and Veber, Alvit and Tzadok, Michal and Nissenkorn, Andreea and Tonduti, Davide and Renaldo, Florence and Kraoua, Ichraf and Panteghini, Celeste and Valletta, Lorella and Garavaglia, Barbara and Cowley, Mark J and Gayevskiy, Velimir and Roscioli, Tony and Silberstein, Jonathon M and Hoffmann, Chen and Raas-Rothschild, Annick and Tiranti, Valeria and Anikster, Yair and Christodoulou, John and Kastaniotis, Alexander J and Ben-Zeev, Bruria and Hayflick, Susan J} }