@article {828, title = {Loss of the neural-specific BAF subunit ACTL6B relieves repression of early response genes and causes recessive autism.}, journal = {Proc Natl Acad Sci U S A}, volume = {117}, year = {2020}, month = {2020 05 05}, pages = {10055-10066}, abstract = {

Synaptic activity in neurons leads to the rapid activation of genes involved in mammalian behavior. ATP-dependent chromatin remodelers such as the BAF complex contribute to these responses and are generally thought to activate transcription. However, the mechanisms keeping such "early activation" genes silent have been a mystery. In the course of investigating Mendelian recessive autism, we identified six families with segregating loss-of-function mutations in the neuronal BAF (nBAF) subunit (originally named ). Accordingly, was the most significantly mutated gene in the Simons Recessive Autism Cohort. At least 14 subunits of the nBAF complex are mutated in autism, collectively making it a major contributor to autism spectrum disorder (ASD). Patient mutations destabilized ACTL6B protein in neurons and rerouted dendrites to the wrong glomerulus in the fly olfactory system. Humans and mice lacking showed corpus callosum hypoplasia, indicating a conserved role for in facilitating neural connectivity. knockout mice on two genetic backgrounds exhibited ASD-related behaviors, including social and memory impairments, repetitive behaviors, and hyperactivity. Surprisingly, mutation of relieved repression of early response genes including AP1 transcription factors (, , , and ), increased chromatin accessibility at AP1 binding sites, and transcriptional changes in late response genes associated with early response transcription factor activity. loss is thus an important cause of recessive ASD, with impaired neuron-specific chromatin repression indicated as a potential mechanism.

}, keywords = {Actins, Adenosine Triphosphate, Animals, Autism Spectrum Disorder, Behavior, Animal, Chromatin, Chromatin Assembly and Disassembly, Chromosomal Proteins, Non-Histone, Chromosome Pairing, Corpus Callosum, Dendrites, Disease Models, Animal, DNA-Binding Proteins, Gene Expression Regulation, Hippocampus, Humans, Mice, Mice, Knockout, Mutation, Neurons, Transcription Factors}, issn = {1091-6490}, doi = {10.1073/pnas.1908238117}, author = {Wenderski, Wendy and Wang, Lu and Krokhotin, Andrey and Walsh, Jessica J and Li, Hongjie and Shoji, Hirotaka and Ghosh, Shereen and George, Renee D and Miller, Erik L and Elias, Laura and Gillespie, Mark A and Son, Esther Y and Staahl, Brett T and Baek, Seung Tae and Stanley, Valentina and Moncada, Cynthia and Shipony, Zohar and Linker, Sara B and Marchetto, Maria C N and Gage, Fred H and Chen, Dillon and Sultan, Tipu and Zaki, MAH S and Ranish, Jeffrey A and Miyakawa, Tsuyoshi and Luo, Liqun and Malenka, Robert C and Crabtree, Gerald R and Gleeson, Joseph G} } @article {391, title = {Heterozygous variants in ACTL6A, encoding a component of the BAF complex, are associated with intellectual disability.}, journal = {Hum Mutat}, volume = {38}, year = {2017}, month = {2017 10}, pages = {1365-1371}, abstract = {

Pathogenic variants in genes encoding components of the BRG1-associated factor (BAF) chromatin remodeling complex have been associated with intellectual disability syndromes. We identified heterozygous, novel variants in ACTL6A, a gene encoding a component of the BAF complex, in three subjects with varying degrees of intellectual disability. Two subjects have missense variants affecting highly conserved amino acid residues within the actin-like domain. Missense mutations in the homologous region in yeast actin were previously reported to be dominant lethal and were associated with impaired binding of the human ACTL6A to β-actin and BRG1. A third subject has a splicing variant that creates an in-frame deletion. Our findings suggest that the variants identified in our subjects may have a deleterious effect on the function of the protein by disturbing the integrity of the BAF complex. Thus, ACTL6A gene mutation analysis should be considered in patients with intellectual disability, learning disabilities, or developmental language disorder.

}, keywords = {Actins, Adolescent, Child, Chromatin Assembly and Disassembly, Chromosomal Proteins, Non-Histone, DNA Helicases, DNA-Binding Proteins, Exome, Face, Female, Hand Deformities, Congenital, Heterozygote, Humans, Intellectual Disability, Male, Micrognathism, Multiprotein Complexes, Mutation, Missense, Nuclear Proteins, Protein Binding, Transcription Factors}, issn = {1098-1004}, doi = {10.1002/humu.23282}, author = {Marom, Ronit and Jain, Mahim and Burrage, Lindsay C and Song, I-Wen and Graham, Brett H and Brown, Chester W and Stevens, Servi J C and Stegmann, Alexander P A and Gunter, Andrew T and Kaplan, Julie D and Gavrilova, Ralitza H and Shinawi, Marwan and Rosenfeld, Jill A and Bae, Yangjin and Tran, Alyssa A and Chen, Yuqing and Lu, James T and Gibbs, Richard A and Eng, Christine and Yang, Yaping and Rousseau, Justine and de Vries, Bert B A and Campeau, Philippe M and Lee, Brendan} } @article {258, title = {Expanding the phenotypic spectrum of ARID1B-mediated disorders and identification of altered cell-cycle dynamics due to ARID1B haploinsufficiency.}, journal = {Orphanet J Rare Dis}, volume = {9}, year = {2014}, month = {2014 Mar 27}, pages = {43}, abstract = {

BACKGROUND: Mutations in genes encoding components of the Brahma-associated factor (BAF) chromatin remodeling complex have recently been shown to contribute to multiple syndromes characterised by developmental delay and intellectual disability. ARID1B mutations have been identified as the predominant cause of Coffin-Siris syndrome and have also been shown to be a frequent cause of nonsyndromic intellectual disability. Here, we investigate the molecular basis of a patient with an overlapping but distinctive phenotype of intellectual disability, plantar fat pads and facial dysmorphism.

METHODS/RESULTS: High density microarray analysis of the patient demonstrated a heterozygous deletion at 6q25.3, which resulted in the loss of four genes including AT Rich Interactive Domain 1B (ARID1B). Subsequent quantitative real-time PCR analysis revealed ARID1B haploinsufficiency in the patient. Analysis of both patient-derived and ARID1B knockdown fibroblasts after serum starvation demonstrated delayed cell cycle re-entry associated with reduced cell number in the S1 phase. Based on the patient{\textquoteright}s distinctive phenotype, we ascertained four additional patients and identified heterozygous de novo ARID1B frameshift or nonsense mutations in all of them.

CONCLUSIONS: This study broadens the spectrum of ARID1B associated phenotypes by describing a distinctive phenotype including plantar fat pads but lacking the hypertrichosis or fifth nail hypoplasia associated with Coffin-Siris syndrome. We present the first direct evidence in patient-derived cells that alterations in cell cycle contribute to the underlying pathogenesis of syndromes associated with ARID1B haploinsufficiency.

}, keywords = {Abnormalities, Multiple, Cell Cycle, Chromatin Assembly and Disassembly, DNA-Binding Proteins, Face, Female, Hand Deformities, Congenital, Haploinsufficiency, Humans, Intellectual Disability, Male, Micrognathism, Neck, Transcription Factors}, issn = {1750-1172}, doi = {10.1186/1750-1172-9-43}, author = {Sim, Joe C H and White, Susan M and Fitzpatrick, Elizabeth and Wilson, Gabrielle R and Gillies, Greta and Pope, Kate and Mountford, Hayley S and Torring, Pernille M and McKee, Shane and Vulto-van Silfhout, Anneke T and Jhangiani, Shalini N and Muzny, Donna M and Leventer, Richard J and Delatycki, Martin B and Amor, David J and Lockhart, Paul J} }