@article {1013, title = {Novel variants in TUBA1A cause congenital fibrosis of the extraocular muscles with or without malformations of cortical brain development.}, journal = {Eur J Hum Genet}, volume = {29}, year = {2021}, month = {2021 May}, pages = {816-826}, abstract = {

Variants in multiple tubulin genes have been implicated in neurodevelopmental disorders, including malformations of cortical development (MCD) and congenital fibrosis of the extraocular muscles (CFEOM). Distinct missense variants in the beta-tubulin encoding genes TUBB3 and TUBB2B cause MCD, CFEOM, or both, suggesting substitution-specific mechanisms. Variants in the alpha tubulin-encoding gene TUBA1A have been associated with MCD, but not with CFEOM. Using exome sequencing (ES) and genome sequencing (GS), we identified 3 unrelated probands with CFEOM who harbored novel heterozygous TUBA1A missense variants c.1216C>G, p.(His406Asp); c.467G>A, p.(Arg156His); and c.1193T>G, p.(Met398Arg). MRI revealed small oculomotor-innervated muscles and asymmetrical caudate heads and lateral ventricles with or without corpus callosal thinning. Two of the three probands had MCD. Mutated amino acid residues localize either to the longitudinal interface at which α and β tubulins heterodimerize (Met398, His406) or to the lateral interface at which tubulin protofilaments interact (Arg156), and His406 interacts with the motor domain of kinesin-1. This series of individuals supports TUBA1A variants as a cause of CFEOM and expands our knowledge of tubulinopathies.

}, issn = {1476-5438}, doi = {10.1038/s41431-020-00804-7}, author = {Jurgens, Julie A and Barry, Brenda J and Lemire, Gabrielle and Chan, Wai-Man and Whitman, Mary C and Shaaban, Sherin and Robson, Caroline D and MacKinnon, Sarah and England, Eleina M and McMillan, Hugh J and Kelly, Christopher and Pratt, Brandon M and O{\textquoteright}Donnell-Luria, Anne and MacArthur, Daniel G and Boycott, Kym M and Hunter, David G and Engle, Elizabeth C} } @article {805, title = {Recurrent Rare Copy Number Variants Increase Risk for Esotropia.}, journal = {Invest Ophthalmol Vis Sci}, volume = {61}, year = {2020}, month = {2020 08 03}, pages = {22}, abstract = {

Purpose: To determine whether rare copy number variants (CNVs) increase risk for comitant esotropia.

Methods: CNVs were identified in 1614 Caucasian individuals with comitant esotropia and 3922 Caucasian controls from Illumina SNP genotyping using two Hidden Markov model (HMM) algorithms, PennCNV and QuantiSNP, which call CNVs based on logR ratio and B allele frequency. Deletions and duplications greater than 10 kb were included. Common CNVs were excluded. Association testing was performed with 1 million permutations in PLINK. Significant CNVs were confirmed with digital droplet polymerase chain reaction (ddPCR). Whole genome sequencing was performed to determine insertion location and breakpoints.

Results: Esotropia patients have similar rates and proportions of CNVs compared with controls but greater total length and average size of both deletions and duplications. Three recurrent rare duplications significantly (P = 1 {\texttimes} 10-6) increase the risk of esotropia: chromosome 2p11.2 (hg19, 2:87428677-87965359), spanning one long noncoding RNA (lncRNA) and two microRNAs (OR 14.16; 95\% confidence interval [CI] 5.4-38.1); chromosome 4p15.2 (hg19, 4:25554332-25577184), spanning one lncRNA (OR 11.1; 95\% CI 4.6-25.2); chromosome 10q11.22 (hg19, 10:47049547-47703870) spanning seven protein-coding genes, one lncRNA, and four pseudogenes (OR 8.96; 95\% CI 5.4-14.9). Overall, 114 cases (7\%) and only 28 controls (0.7\%) had one of the three rare duplications. No case nor control had more than one of these three duplications.

Conclusions: Rare CNVs are a source of genetic variation that contribute to the genetic risk for comitant esotropia, which is likely polygenic. Future research into the functional consequences of these recurrent duplications may shed light on the pathophysiology of esotropia.

}, keywords = {Case-Control Studies, DNA Copy Number Variations, Esotropia, Female, Gene Duplication, Gene Frequency, Genetic Predisposition to Disease, Genotyping Techniques, Humans, Infant, Male, Markov Chains, Polymerase Chain Reaction, Risk Factors}, issn = {1552-5783}, doi = {10.1167/iovs.61.10.22}, author = {Whitman, Mary C and Di Gioia, Silvio Alessandro and Chan, Wai-Man and Gelber, Alon and Pratt, Brandon M and Bell, Jessica L and Collins, Thomas E and Knowles, James A and Armoskus, Christopher and Pato, Michele and Pato, Carlos and Shaaban, Sherin and Staffieri, Sandra and MacKinnon, Sarah and Maconachie, Gail D E and Elder, James E and Traboulsi, Elias I and Gottlob, Irene and Mackey, David A and Hunter, David G and Engle, Elizabeth C} } @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} }