@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 {359, title = {Kaufman oculo-cerebro-facial syndrome in a child with small and absent terminal phalanges and absent nails.}, journal = {J Hum Genet}, volume = {62}, year = {2017}, month = {2017 Apr}, pages = {465-471}, abstract = {

Kaufman oculo-cerebro-facial syndrome (KOS) is caused by recessive UBE3B mutations and presents with microcephaly, ocular abnormalities, distinctive facial morphology, low cholesterol levels and intellectual disability. We describe a child with microcephaly, brachycephaly, hearing loss, ptosis, blepharophimosis, hypertelorism, cleft palate, multiple renal cysts, absent nails, small or absent terminal phalanges, absent speech and intellectual disability. Syndromes that were initially considered include DOORS syndrome, Coffin-Siris syndrome and Dubowitz syndrome. Clinical investigations coupled with karyotype analysis, array-comparative genomic hybridization, exome and Sanger sequencing were performed to characterize the condition in this child. Sanger sequencing was negative for the DOORS syndrome gene TBC1D24 but exome sequencing identified a homozygous deletion in UBE3B (NM_183415:c.3139_3141del, p.1047_1047del) located within the terminal portion of the HECT domain. This finding coupled with the presence of characteristic features such as brachycephaly, ptosis, blepharophimosis, hypertelorism, short palpebral fissures, cleft palate and developmental delay allowed us to make a diagnosis of KOS. In conclusion, our findings highlight the importance of considering KOS as a differential diagnosis for patients under evaluation for DOORS syndrome and expand the phenotype of KOS to include small or absent terminal phalanges, nails, and the presence of hallux varus and multicystic dysplastic kidneys.

}, keywords = {Abnormalities, Multiple, Adult, Carrier Proteins, Child, Child, Preschool, Diagnosis, Differential, Eczema, Eye Abnormalities, Face, Facies, Female, Growth Disorders, Hand Deformities, Congenital, Humans, Intellectual Disability, Karyotype, Limb Deformities, Congenital, Male, Microcephaly, Micrognathism, Mutation, Neck, Pathology, Molecular, Sequence Analysis, DNA, Ubiquitin-Protein Ligases}, issn = {1435-232X}, doi = {10.1038/jhg.2016.151}, author = {Kariminejad, Ariana and Ajeawung, Norbert Fonya and Bozorgmehr, Bita and Dionne-Laporte, Alexandre and Molidperee, Sirinart and Najafi, Kimia and Gibbs, Richard A and Lee, Brendan H and Hennekam, Raoul C and Campeau, Philippe M} } @article {126, title = {Gonadal mosaicism in ARID1B gene causes intellectual disability and dysmorphic features in three siblings.}, journal = {Am J Med Genet A}, volume = {170A}, year = {2016}, month = {2016 Jan}, pages = {156-61}, abstract = {

The gene encoding the AT-rich interaction domain-containing protein 1B (ARID1B) has recently been shown to be one of the most frequently mutated genes in patients with intellectual disability (ID). The phenotypic spectrums associated with variants in this gene vary widely ranging for mild to severe non-specific ID to Coffin-Siris syndrome. In this study, we evaluated three children from a consanguineous Emirati family affected with ID and dysmorphic features. Genomic DNA from all affected siblings was analyzed using CGH array and whole-exome sequencing (WES). Based on a recessive mode of inheritance, homozygous or compound heterozygous variants shared among all three affected children could not be identified. However, further analysis revealed a heterozygous variant (c.4318C>T; p.Q1440*) in the three affected children in an autosomal dominant ID causing gene, ARID1B. This variant was absent in peripheral blood samples obtained from both parents and unaffected siblings. Therefore, we propose that the most likely explanation for this situation is that one of the parents is a gonadal mosaic for the variant. To the best of our knowledge, this is the first report of a gonadal mosaicism inheritance of an ARID1B variant leading to familial ID recurrence.

}, keywords = {Abnormalities, Multiple, Adolescent, Child, DNA-Binding Proteins, Exome, Face, Female, Hand Deformities, Congenital, Heterozygote, Humans, Intellectual Disability, Male, Micrognathism, Mosaicism, Mutation, Neck, Pedigree, Siblings, Transcription Factors}, issn = {1552-4833}, doi = {10.1002/ajmg.a.37405}, author = {Ben-Salem, Salma and Sobreira, Nara and Akawi, Nadia A and Al-Shamsi, Aisha M and John, Anne and Pramathan, Thachillath and Valle, David and Ali, Bassam R and Al-Gazali, Lihadh} } @article {108, title = {De Novo GMNN Mutations Cause Autosomal-Dominant Primordial Dwarfism Associated with Meier-Gorlin Syndrome.}, journal = {Am J Hum Genet}, volume = {97}, year = {2015}, month = {2015 Dec 03}, pages = {904-13}, abstract = {

Meier-Gorlin syndrome (MGS) is a genetically heterogeneous primordial dwarfism syndrome known to be caused by biallelic loss-of-function mutations in one of five genes encoding pre-replication complex proteins: ORC1, ORC4, ORC6, CDT1, and CDC6. Mutations in these genes cause disruption of the origin of DNA replication initiation. To date, only an autosomal-recessive inheritance pattern has been described in individuals with this disorder, with a molecular etiology established in about three-fourths of cases. Here, we report three subjects with MGS and de novo heterozygous mutations in the 5{\textquoteright} end of GMNN, encoding the DNA replication inhibitor geminin. We identified two truncating mutations in exon 2 (the 1(st) coding exon), c.16A>T (p.Lys6(*)) and c.35_38delTCAA (p.Ile12Lysfs(*)4), and one missense mutation, c.50A>G (p.Lys17Arg), affecting the second-to-last nucleotide of exon 2 and possibly RNA splicing. Geminin is present during the S, G2, and M phases of the cell cycle and is degraded during the metaphase-anaphase transition by the anaphase-promoting complex (APC), which recognizes the destruction box sequence near the 5{\textquoteright} end of the geminin protein. All three GMNN mutations identified alter sites 5{\textquoteright} to residue Met28 of the protein, which is located within the destruction box. We present data supporting a gain-of-function mechanism, in which the GMNN mutations result in proteins lacking the destruction box and hence increased protein stability and prolonged inhibition of replication leading to autosomal-dominant MGS.

}, keywords = {Adolescent, Amino Acid Sequence, Base Sequence, Cell Cycle, Child, Preschool, Congenital Microtia, Dwarfism, Exons, Female, Geminin, Gene Expression, Genes, Dominant, Growth Disorders, Heterozygote, High-Throughput Nucleotide Sequencing, Humans, Inheritance Patterns, Male, Micrognathism, Molecular Sequence Data, Mutation, Patella, Pedigree, Protein Stability, Proteolysis, RNA Splicing, Sequence Alignment}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.11.006}, author = {Burrage, Lindsay C and Charng, Wu-Lin and Eldomery, Mohammad K and Willer, Jason R and Davis, Erica E and Lugtenberg, Dorien and Zhu, Wenmiao and Leduc, Magalie S and Akdemir, Zeynep C and Azamian, Mahshid and Zapata, Gladys and Hernandez, Patricia P and Schoots, Jeroen and de Munnik, Sonja A and Roepman, Ronald and Pearring, Jillian N and Jhangiani, Shalini and Katsanis, Nicholas and Vissers, Lisenka E L M and Brunner, Han G and Beaudet, Arthur L and Rosenfeld, Jill A and Muzny, Donna M and Gibbs, Richard A and Eng, Christine M and Xia, Fan and Lalani, Seema R and Lupski, James R and Bongers, Ernie M H F and Yang, Yaping} } @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} }