@article {336, title = {Multilevel analyses of SCN5A mutations in arrhythmogenic right ventricular dysplasia/cardiomyopathy suggest non-canonical mechanisms for disease pathogenesis.}, journal = {Cardiovasc Res}, volume = {113}, year = {2017}, month = {2017 01}, pages = {102-111}, abstract = {

AIMS: Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) is often associated with desmosomal mutations. Recent studies suggest an interaction between the desmosome and sodium channel protein Na1.5. We aimed to determine the prevalence and biophysical properties of mutations in SCN5A (the gene encoding Na1.5) in ARVD/C.

METHODS AND RESULTS: We performed whole-exome sequencing in six ARVD/C patients (33\% male, 38.2 {\textpm} 12.1 years) without a desmosomal mutation. We found a rare missense variant (p.Arg1898His; R1898H) in SCN5A in one patient. We generated induced pluripotent stem cell-derived cardiomyocytes (hIPSC-CMs) from the patient{\textquoteright}s peripheral blood mononuclear cells. The variant was then corrected (R1898R) using Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 technology, allowing us to study the impact of the R1898H substitution in the same cellular background. Whole-cell patch clamping revealed a 36\% reduction in peak sodium current (P = 0.002); super-resolution fluorescence microscopy showed reduced abundance of Na1.5 (P = 0.005) and N-Cadherin (P = 0.026) clusters at the intercalated disc. Subsequently, we sequenced SCN5A in an additional 281 ARVD/C patients (60\% male, 34.8 {\textpm} 13.7 years, 52\% desmosomal mutation-carriers). Five (1.8\%) subjects harboured a putatively pathogenic SCN5A variant (p.Tyr416Cys, p.Leu729del, p.Arg1623Ter, p.Ser1787Asn, and p.Val2016Met). SCN5A variants were associated with prolonged QRS duration (119 {\textpm} 15 vs. 94 {\textpm} 14 ms, P < 0.01) and all SCN5A variant carriers had major structural abnormalities on cardiac imaging.

CONCLUSIONS: Almost 2\% of ARVD/C patients harbour rare SCN5A variants. For one of these variants, we demonstrated reduced sodium current, Na1.5 and N-Cadherin clusters at junctional sites. This suggests that Na1.5 is in a functional complex with adhesion molecules, and reveals potential non-canonical mechanisms by which Na1.5 dysfunction causes cardiomyopathy.

}, keywords = {Adult, Antigens, CD, Arrhythmogenic Right Ventricular Dysplasia, Cadherins, Cell Differentiation, CRISPR-Cas Systems, DNA Mutational Analysis, Electrocardiography, Exome, Female, Gene Editing, Gene Frequency, Genetic Predisposition to Disease, Genome-Wide Association Study, HEK293 Cells, Humans, Induced Pluripotent Stem Cells, Magnetic Resonance Imaging, Male, Membrane Potentials, Middle Aged, Multilevel Analysis, Mutation, Missense, Myocytes, Cardiac, NAV1.5 Voltage-Gated Sodium Channel, Netherlands, Phenotype, Sodium, Transfection, United States, Young Adult}, issn = {1755-3245}, doi = {10.1093/cvr/cvw234}, author = {Te Riele, Anneline S J M and Agullo-Pascual, Esperanza and James, Cynthia A and Leo-Macias, Alejandra and Cerrone, Marina and Zhang, Mingliang and Lin, Xianming and Lin, Bin and Sobreira, Nara L and Amat-Alarcon, Nuria and Marsman, Roos F and Murray, Brittney and Tichnell, Crystal and van der Heijden, Jeroen F and Dooijes, Dennis and van Veen, Toon A B and Tandri, Harikrishna and Fowler, Steven J and Hauer, Richard N W and Tomaselli, Gordon and van den Berg, Maarten P and Taylor, Matthew R G and Brun, Francesca and Sinagra, Gianfranco and Wilde, Arthur A M and Mestroni, Luisa and Bezzina, Connie R and Calkins, Hugh and Peter van Tintelen, J and Bu, Lei and Delmar, Mario and Judge, Daniel P} } @article {63, title = {PYCR2 Mutations cause a lethal syndrome of microcephaly and failure to thrive.}, journal = {Ann Neurol}, volume = {80}, year = {2016}, month = {2016 07}, pages = {59-70}, abstract = {

OBJECTIVE: A study was undertaken to characterize the clinical features of the newly described hypomyelinating leukodystrophy type 10 with microcephaly. This is an autosomal recessive disorder mapped to chromosome 1q42.12 due to mutations in the PYCR2 gene, encoding an enzyme involved in proline synthesis in mitochondria.

METHODS: From several international clinics, 11 consanguineous families were identified with PYCR2 mutations by whole exome or targeted sequencing, with detailed clinical and radiological phenotyping. Selective mutations from patients were tested for effect on protein function.

RESULTS: The characteristic clinical presentation of patients with PYCR2 mutations included failure to thrive, microcephaly, craniofacial dysmorphism, progressive psychomotor disability, hyperkinetic movements, and axial hypotonia with variable appendicular spasticity. Patients did not survive beyond the first decade of life. Brain magnetic resonance imaging showed global brain atrophy and white matter T2 hyperintensities. Routine serum metabolic profiles were unremarkable. Both nonsense and missense mutations were identified, which impaired protein multimerization.

INTERPRETATION: PYCR2-related syndrome represents a clinically recognizable condition in which PYCR2 mutations lead to protein dysfunction, not detectable on routine biochemical assessments. Mutations predict a poor outcome, probably as a result of impaired mitochondrial function. Ann Neurol 2016;80:59-70.

}, keywords = {Adolescent, Child, Child, Preschool, Codon, Nonsense, Exome, Failure to Thrive, Female, Fibroblasts, Gene Expression, Genetic Predisposition to Disease, Genotype, Humans, Infant, Male, Microcephaly, Mutation, Missense, Phenotype, Primary Cell Culture, Pyrroline Carboxylate Reductases, Syndrome, Transfection, Young Adult}, issn = {1531-8249}, doi = {10.1002/ana.24678}, author = {Zaki, Maha S and Bhat, Gifty and Sultan, Tipu and Issa, Mahmoud and Jung, Hea-Jin and Dikoglu, Esra and Selim, Laila and G Mahmoud, Imam and Abdel-Hamid, Mohamed S and Abdel-Salam, Ghada and Marin-Valencia, Isaac and Gleeson, Joseph G} } @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} } @article {148, title = {An siRNA-based functional genomics screen for the~identification of regulators of ciliogenesis and ciliopathy~genes.}, journal = {Nat Cell Biol}, volume = {17}, year = {2015}, month = {2015 Aug}, pages = {1074-1087}, abstract = {

Defects in primary cilium biogenesis underlie the ciliopathies, a growing group of genetic disorders. We describe a whole-genome siRNA-based reverse genetics screen for defects in biogenesis and/or maintenance of the primary cilium, obtaining a global resource. We identify 112 candidate ciliogenesis and ciliopathy genes, including 44 components of the ubiquitin-proteasome system, 12 G-protein-coupled receptors, and 3 pre-mRNA processing factors (PRPF6, PRPF8 and PRPF31) mutated in autosomal dominant retinitis pigmentosa. The PRPFs localize to the connecting cilium, and PRPF8- and PRPF31-mutated cells have ciliary defects. Combining the screen with exome sequencing data identified recessive mutations in PIBF1, also known as CEP90, and C21orf2, also known as LRRC76, as causes of the ciliopathies Joubert and Jeune syndromes. Biochemical approaches place C21orf2 within key ciliopathy-associated protein modules, offering an explanation for the skeletal and retinal involvement observed in individuals with C21orf2 variants. Our global, unbiased approaches provide insights into ciliogenesis complexity and identify roles for unanticipated pathways in human genetic disease.

}, keywords = {Abnormalities, Multiple, Animals, Caenorhabditis elegans, Cerebellar Diseases, Cerebellum, Cilia, Ciliary Motility Disorders, Databases, Genetic, Ellis-Van Creveld Syndrome, Eye Abnormalities, Genetic Markers, Genetic Predisposition to Disease, Genetic Testing, Genome-Wide Association Study, Genomics, HEK293 Cells, High-Throughput Nucleotide Sequencing, Humans, Kidney Diseases, Cystic, Membrane Proteins, Mice, Inbred C57BL, Mice, Knockout, Mutation, Phenotype, Photoreceptor Cells, Pregnancy Proteins, Proteins, Reproducibility of Results, Retina, RNA Interference, Suppressor Factors, Immunologic, Transfection, Zebrafish}, issn = {1476-4679}, doi = {10.1038/ncb3201}, author = {Wheway, Gabrielle and Schmidts, Miriam and Mans, Dorus A and Szymanska, Katarzyna and Nguyen, Thanh-Minh T and Racher, Hilary and Phelps, Ian G and Toedt, Grischa and Kennedy, Julie and Wunderlich, Kirsten A and Sorusch, Nasrin and Abdelhamed, Zakia A and Natarajan, Subaashini and Herridge, Warren and van Reeuwijk, Jeroen and Horn, Nicola and Boldt, Karsten and Parry, David A and Letteboer, Stef J F and Roosing, Susanne and Adams, Matthew and Bell, Sandra M and Bond, Jacquelyn and Higgins, Julie and Morrison, Ewan E and Tomlinson, Darren C and Slaats, Gisela G and van Dam, Teunis J P and Huang, Lijia and Kessler, Kristin and Giessl, Andreas and Logan, Clare V and Boyle, Evan A and Shendure, Jay and Anazi, Shamsa and Aldahmesh, Mohammed and Al Hazzaa, Selwa and Hegele, Robert A and Ober, Carole and Frosk, Patrick and Mhanni, Aizeddin A and Chodirker, Bernard N and Chudley, Albert E and Lamont, Ryan and Bernier, Francois P and Beaulieu, Chandree L and Gordon, Paul and Pon, Richard T and Donahue, Clem and Barkovich, A James and Wolf, Louis and Toomes, Carmel and Thiel, Christian T and Boycott, Kym M and McKibbin, Martin and Inglehearn, Chris F and Stewart, Fiona and Omran, Heymut and Huynen, Martijn A and Sergouniotis, Panagiotis I and Alkuraya, Fowzan S and Parboosingh, Jillian S and Innes, A Micheil and Willoughby, Colin E and Giles, Rachel H and Webster, Andrew R and Ueffing, Marius and Blacque, Oliver and Gleeson, Joseph G and Wolfrum, Uwe and Beales, Philip L and Gibson, Toby and Doherty, Dan and Mitchison, Hannah M and Roepman, Ronald and Johnson, Colin A} }