@article {819, title = { Gain-of-Function Variants in Dilated Cardiomyopathy.}, journal = {Circ Genom Precis Med}, volume = {13}, year = {2020}, month = {2020 08}, pages = {e002892}, abstract = {

BACKGROUND: Dilated cardiomyopathy (DCM) is a genetically heterogeneous cardiac disease characterized by progressive ventricular enlargement and reduced systolic function. Here, we report genetic and functional analyses implicating the rat sarcoma signaling protein, SOS1 (Son of sevenless homolog 1), in DCM pathogenesis.

METHODS: Exome sequencing was performed on 412 probands and family members from our DCM cohort, identifying several variants with potential disease involvement. As several lines of evidence have implicated dysregulated rat sarcoma signaling in the pathogenesis of DCM, we assessed functional impact of each variant on the activation of ERK (extracellular signal-regulated kinase), AKT (protein kinase B), and JNK (c-Jun N-terminal kinase) pathways. Relative expression levels were determined by Western blot in HEK293T cells transfected with variant or wild-type human expression constructs.

RESULTS: A rare variant [c.571G>A, p.(Glu191Lys)] was found to segregate alongside an A-band truncating variant in a pedigree with aggressive, early-onset DCM. Reduced disease severity in the absence of the variant suggested its potential involvement as a genetic risk factor for DCM in this family. Exome sequencing identified 5 additional variants with potential disease involvement in 4 other families [c.1820T>C, p.(Ile607Thr); c.2156G>C, p.(Gly719Ala); c.2230A>G, p.(Arg744Gly); c.2728G>C, p.(Asp910His); c.3601C>T, p.(Arg1201Trp)]. Impacted amino acids occupied a number of functional domains relevant to SOS1 activity, including the N-terminal histone fold, as well as the C-terminal REM (rat sarcoma exchange motif), CDC25 (cell division cycle 25), and PR (proline-rich) tail domains. Increased phosphorylated ERK expression relative to wild-type levels was seen for all 6 variants, paralleling known disease-relevant signaling profiles.

CONCLUSIONS: These data support gain-of-function variation in as a contributing factor to isolated DCM.

}, issn = {2574-8300}, doi = {10.1161/CIRCGEN.119.002892}, author = {Cowan, Jason R and Salyer, Lorien and Wright, Nathan T and Kinnamon, Daniel D and Amaya, Pedro and Jordan, Elizabeth and Bamshad, Michael J and Nickerson, Deborah A and Hershberger, Ray E} } @article {573, title = {Biallelic VARS variants cause developmental encephalopathy with microcephaly that is recapitulated in vars knockout zebrafish.}, journal = {Nat Commun}, volume = {10}, year = {2019}, month = {2019 02 12}, pages = {708}, abstract = {

Aminoacyl tRNA synthetases (ARSs) link specific amino acids with their cognate transfer RNAs in a critical early step of protein translation. Mutations in ARSs have emerged as a cause of recessive, often complex neurological disease traits. Here we report an allelic series consisting of seven novel and two previously reported biallelic variants in valyl-tRNA synthetase (VARS) in ten patients with a developmental encephalopathy with microcephaly, often associated with early-onset epilepsy. In silico, in vitro, and yeast complementation assays demonstrate that the underlying pathomechanism of these mutations is most likely a loss of protein function. Zebrafish modeling accurately recapitulated some of the key neurological disease traits. These results provide both genetic and biological insights into neurodevelopmental disease and pave the way for further in-depth research on ARS related recessive disorders and precision therapies.

}, keywords = {Alleles, Animals, Brain Diseases, Cell Line, Disease Models, Animal, Epilepsy, Female, Fibroblasts, Gene Knockout Techniques, Genetic Predisposition to Disease, Humans, Loss of Function Mutation, Male, Microcephaly, Models, Molecular, Neurodevelopmental Disorders, Pedigree, Prosencephalon, Valine-tRNA Ligase, Zebrafish}, issn = {2041-1723}, doi = {10.1038/s41467-018-07953-w}, author = {Siekierska, Aleksandra and Stamberger, Hannah and Deconinck, Tine and Oprescu, Stephanie N and Partoens, Mich{\`e}le and Zhang, Yifan and Sourbron, Jo and Adriaenssens, Elias and Mullen, Patrick and Wiencek, Patrick and Hardies, Katia and Lee, Jeong-Soo and Giong, Hoi-Khoanh and Distelmaier, Felix and Elpeleg, Orly and Helbig, Katherine L and Hersh, Joseph and Isikay, Sedat and Jordan, Elizabeth and Karaca, Ender and Kecskes, Angela and Lupski, James R and Kovacs-Nagy, Reka and May, Patrick and Narayanan, Vinodh and Pendziwiat, Manuela and Ramsey, Keri and Rangasamy, Sampathkumar and Shinde, Deepali N and Spiegel, Ronen and Timmerman, Vincent and von Spiczak, Sarah and Helbig, Ingo and Weckhuysen, Sarah and Francklyn, Christopher and Antonellis, Anthony and de Witte, Peter and De Jonghe, Peter} }