@article {1022, title = {POLRMT mutations impair mitochondrial transcription causing neurological disease.}, journal = {Nat Commun}, volume = {12}, year = {2021}, month = {2021 02 18}, pages = {1135}, abstract = {

While >300 disease-causing variants have been identified in the mitochondrial DNA (mtDNA) polymerase γ, no mitochondrial phenotypes have been associated with POLRMT, the RNA polymerase responsible for transcription of the mitochondrial genome. Here, we characterise the clinical and molecular nature of POLRMT variants in eight individuals from seven unrelated families. Patients present with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood; one subject displayed an indolent progressive external ophthalmoplegia phenotype. Massive parallel sequencing of all subjects identifies recessive and dominant variants in the POLRMT gene. Patient fibroblasts have a defect in mitochondrial mRNA synthesis, but no mtDNA deletions or copy number abnormalities. The in vitro characterisation of the recombinant POLRMT mutants reveals variable, but deleterious effects on mitochondrial transcription. Together, our in vivo and in vitro functional studies of POLRMT variants establish defective mitochondrial transcription as an important disease mechanism.

}, keywords = {Adolescent, Adult, Child, DNA, Mitochondrial, DNA-Directed RNA Polymerases, Female, Fibroblasts, Humans, Infant, Male, Mitochondria, Mutation, Nervous System Diseases, Oxidative Phosphorylation, Pedigree, Protein Domains, Protein Subunits, RNA, Messenger, Transcription, Genetic, Young Adult}, issn = {2041-1723}, doi = {10.1038/s41467-021-21279-0}, author = {Ol{\'a}hov{\'a}, Monika and Peter, Bradley and Szilagyi, Zsolt and Diaz-Maldonado, Hector and Singh, Meenakshi and Sommerville, Ewen W and Blakely, Emma L and Collier, Jack J and Hoberg, Emily and Str{\'a}neck{\'y}, Viktor and Hartmannov{\'a}, Hana and Bleyer, Anthony J and McBride, Kim L and Bowden, Sasigarn A and Korandov{\'a}, Zuzana and Pecinov{\'a}, Alena and Ropers, Hans-Hilger and Kahrizi, Kimia and Najmabadi, Hossein and Tarnopolsky, Mark A and Brady, Lauren I and Weaver, K Nicole and Prada, Carlos E and {\~O}unap, Katrin and Wojcik, Monica H and Pajusalu, Sander and Syeda, Safoora B and Pais, Lynn and Estrella, Elicia A and Bruels, Christine C and Kunkel, Louis M and Kang, Peter B and Bonnen, Penelope E and Mr{\'a}{\v c}ek, Tom{\'a}{\v s} and Kmoch, Stanislav and Gorman, Gr{\'a}inne S and Falkenberg, Maria and Gustafsson, Claes M and Taylor, Robert W} } @article {580, title = {De novo and inherited TCF20 pathogenic variants are associated with intellectual disability, dysmorphic features, hypotonia, and neurological impairments with similarities to Smith-Magenis syndrome.}, journal = {Genome Med}, volume = {11}, year = {2019}, month = {2019 02 28}, pages = {12}, abstract = {

BACKGROUND: Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity).

METHODS: Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes.

RESULTS: We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances.

CONCLUSIONS: TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.

}, keywords = {Adolescent, Child, Child, Preschool, Craniofacial Abnormalities, Developmental Disabilities, Female, Humans, INDEL Mutation, Infant, Intellectual Disability, Male, Muscle Hypotonia, Smith-Magenis Syndrome, Transcription Factors, Young Adult}, issn = {1756-994X}, doi = {10.1186/s13073-019-0623-0}, author = {Vetrini, Francesco and McKee, Shane and Rosenfeld, Jill A and Suri, Mohnish and Lewis, Andrea M and Nugent, Kimberly Margaret and Roeder, Elizabeth and Littlejohn, Rebecca O and Holder, Sue and Zhu, Wenmiao and Alaimo, Joseph T and Graham, Brett and Harris, Jill M and Gibson, James B and Pastore, Matthew and McBride, Kim L and Komara, Makanko and Al-Gazali, Lihadh and Al Shamsi, Aisha and Fanning, Elizabeth A and Wierenga, Klaas J and Scott, Daryl A and Ben-Neriah, Ziva and Meiner, Vardiella and Cassuto, Hanoch and Elpeleg, Orly and Holder, J Lloyd and Burrage, Lindsay C and Seaver, Laurie H and Van Maldergem, Lionel and Mahida, Sonal and Soul, Janet S and Marlatt, Margaret and Matyakhina, Ludmila and Vogt, Julie and Gold, June-Anne and Park, Soo-Mi and Varghese, Vinod and Lampe, Anne K and Kumar, Ajith and Lees, Melissa and Holder-Espinasse, Muriel and McConnell, Vivienne and Bernhard, Birgitta and Blair, Ed and Harrison, Victoria and Muzny, Donna M and Gibbs, Richard A and Elsea, Sarah H and Posey, Jennifer E and Bi, Weimin and Lalani, Seema and Xia, Fan and Yang, Yaping and Eng, Christine M and Lupski, James R and Liu, Pengfei} } @article {13, title = {A genome-wide association study of congenital cardiovascular left-sided lesions shows association with a locus on chromosome 20.}, journal = {Hum Mol Genet}, volume = {25}, year = {2016}, month = {2016 06 01}, pages = {2331-2341}, abstract = {

Congenital heart defects involving left-sided lesions (LSLs) are relatively common birth defects with substantial morbidity and mortality. Previous studies have suggested a high heritability with a complex genetic architecture, such that only a few LSL loci have been identified. We performed a genome-wide case-control association study to address the role of common variants using a discovery cohort of 778 cases and 2756 controls. We identified a genome-wide significant association mapping to a 200 kb region on chromosome 20q11 [P= 1.72 {\texttimes} 10 for rs3746446; imputed Single Nucleotide Polymorphism (SNP) rs6088703 P= 3.01 {\texttimes} 10, odds ratio (OR)= 1.6 for both]. This result was supported by transmission disequilibrium analyses using a subset of 541 case families (lowest P in region= 4.51 {\texttimes} 10, OR= 1.5). Replication in a cohort of 367 LSL cases and 5159 controls showed nominal association (P= 0.03 for rs3746446) resulting in P= 9.49 {\texttimes} 10 for rs3746446 upon meta-analysis of the combined cohorts. In addition, a group of seven SNPs on chromosome 1q21.3 met threshold for suggestive association (lowest P= 9.35 {\texttimes} 10 for rs12045807). Both regions include genes involved in cardiac development-MYH7B/miR499A on chromosome 20 and CTSK, CTSS and ARNT on chromosome 1. Genome-wide heritability analysis using case-control genotyped SNPs suggested that the mean heritability of LSLs attributable to common variants is moderately high ([Formula: see text] range= 0.26-0.34) and consistent with previous assertions. These results provide evidence for the role of common variation in LSLs, proffer new genes as potential biological candidates, and give further insight to the complex genetic architecture of congenital heart disease.

}, keywords = {Chromosome Mapping, Chromosomes, Human, Pair 20, Cohort Studies, Female, Genetic Predisposition to Disease, Genome-Wide Association Study, Genotype, Heart Defects, Congenital, Heart Ventricles, Humans, Male, Polymorphism, Single Nucleotide}, issn = {1460-2083}, doi = {10.1093/hmg/ddw071}, author = {Hanchard, Neil A and Swaminathan, Shanker and Bucasas, Kristine and Furthner, Dieter and Fernbach, Susan and Azamian, Mahshid S and Wang, Xueqing and Lewin, Mark and Towbin, Jeffrey A and D{\textquoteright}Alessandro, Lisa C A and Morris, Shaine A and Dreyer, William and Denfield, Susan and Ayres, Nancy A and Franklin, Wayne J and Justino, Henri and Lantin-Hermoso, M Regina and Ocampo, Elena C and Santos, Alexia B and Parekh, Dhaval and Moodie, Douglas and Jeewa, Aamir and Lawrence, Emily and Allen, Hugh D and Penny, Daniel J and Fraser, Charles D and Lupski, James R and Popoola, Mojisola and Wadhwa, Lalita and Brook, J David and Bu{\textquoteright}Lock, Frances A and Bhattacharya, Shoumo and Lalani, Seema R and Zender, Gloria A and Fitzgerald-Butt, Sara M and Bowman, Jessica and Corsmeier, Don and White, Peter and Lecerf, Kelsey and Zapata, Gladys and Hernandez, Patricia and Goodship, Judith A and Garg, Vidu and Keavney, Bernard D and Leal, Suzanne M and Cordell, Heather J and Belmont, John W and McBride, Kim L} }