Publications by authors named "Keren Machol"

13 Publications

  • Page 1 of 1

Evidence that FGFRL1 contributes to congenital diaphragmatic hernia development in humans.

Am J Med Genet A 2021 03 14;185(3):836-840. Epub 2021 Jan 14.

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.

Fibroblast growth factor receptor-like 1 (FGFRL1) encodes a transmembrane protein that is related to fibroblast growth factor receptors but lacks an intercellular tyrosine kinase domain. in vitro studies suggest that FGFRL1 inhibits cell proliferation and promotes cell differentiation and cell adhesion. Mice that lack FGFRL1 die shortly after birth from respiratory distress and have abnormally thin diaphragms whose muscular hypoplasia allows the liver to protrude into the thoracic cavity. Haploinsufficiency of FGFRL1 has been hypothesized to contribute to the development of congenital diaphragmatic hernia (CDH) associated with Wolf-Hirschhorn syndrome. However, data from both humans and mice suggest that disruption of one copy of FGFRL1 alone is insufficient to cause diaphragm defects. Here we report a female fetus with CDH whose 4p16.3 deletion allows us to refine the Wolf-Hirschhorn syndrome CDH critical region to an approximately 1.9 Mb region that contains FGFRL1. We also report a male infant with isolated left-sided diaphragm agenesis who carried compound heterozygous missense variants in FGFRL1. These cases provide additional evidence that deleterious FGFRL1 variants may contribute to the development of CDH in humans.
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http://dx.doi.org/10.1002/ajmg.a.62066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8011624PMC
March 2021

Deficient histone H3 propionylation by BRPF1-KAT6 complexes in neurodevelopmental disorders and cancer.

Sci Adv 2020 01 22;6(4):eaax0021. Epub 2020 Jan 22.

Center for Medical Genetics, Ghent University and Ghent University Hospital, C. Heymanslaan 10, B-9000 Ghent, Belgium.

Lysine acetyltransferase 6A (KAT6A) and its paralog KAT6B form stoichiometric complexes with bromodomain- and PHD finger-containing protein 1 (BRPF1) for acetylation of histone H3 at lysine 23 (H3K23). We report that these complexes also catalyze H3K23 propionylation in vitro and in vivo. Immunofluorescence microscopy and ATAC-See revealed the association of this modification with active chromatin. deletion obliterates the acylation in mouse embryos and fibroblasts. Moreover, we identify variants in 12 previously unidentified cases of syndromic intellectual disability and demonstrate that these cases and known variants impair H3K23 propionylation. Cardiac anomalies are present in a subset of the cases. H3K23 acylation is also impaired by cancer-derived somatic mutations. Valproate, vorinostat, propionate and butyrate promote H3K23 acylation. These results reveal the dual functionality of BRPF1-KAT6 complexes, shed light on mechanisms underlying related developmental disorders and various cancers, and suggest mutation-based therapy for medical conditions with deficient histone acylation.
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http://dx.doi.org/10.1126/sciadv.aax0021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6976298PMC
January 2020

Hearing loss in individuals with osteogenesis imperfecta in North America: Results from a multicenter study.

Am J Med Genet A 2020 04 26;182(4):697-704. Epub 2019 Dec 26.

Department of Pediatric Orthopedic Surgery, Hospital for Special Surgery, New York, New York.

Hearing loss (HL) is an extra-skeletal manifestation of the connective tissue disorder osteogenesis imperfecta (OI). Systematic evaluation of the prevalence and characteristics of HL in COL1A1/COL1A2-related OI will contribute to a better clinical management of individuals with OI. We collected and analyzed pure-tone audiometry data from 312 individuals with OI who were enrolled in the Linked Clinical Research Centers and the Brittle Bone Disorders Consortium. The prevalence, type, and severity of HL in COL1A1/COL1A2-related OI are reported. We show that the prevalence of HL in OI is 28% and increased with age in Type I OI but not in Types III and IV. Individuals with OI Types III and IV are at a higher risk to develop HL in the first decade of life when compared to OI Type I. We also show that the prevalence of SNHL is higher in females with OI compared to males. This study reveals new insights regarding prevalence of HL in OI including a lower general prevalence of HL in COL1A1/COL1A2-related OI than previously reported (28.3 vs. 65%) and high prevalence of SNHL in females. Our data support the need in early routine hearing evaluation in all types of OI that can be adjusted to the severity of the skeletal disease.
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http://dx.doi.org/10.1002/ajmg.a.61464DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7385724PMC
April 2020

Widening of the genetic and clinical spectrum of Lamb-Shaffer syndrome, a neurodevelopmental disorder due to SOX5 haploinsufficiency.

Genet Med 2020 03 3;22(3):524-537. Epub 2019 Oct 3.

CHU de Rennes, service de génétique clinique, Rennes, France.

Purpose: Lamb-Shaffer syndrome (LAMSHF) is a neurodevelopmental disorder described in just over two dozen patients with heterozygous genetic alterations involving SOX5, a gene encoding a transcription factor regulating cell fate and differentiation in neurogenesis and other discrete developmental processes. The genetic alterations described so far are mainly microdeletions. The present study was aimed at increasing our understanding of LAMSHF, its clinical and genetic spectrum, and the pathophysiological mechanisms involved.

Methods: Clinical and genetic data were collected through GeneMatcher and clinical or genetic networks for 41 novel patients harboring various types ofSOX5 alterations. Functional consequences of selected substitutions were investigated.

Results: Microdeletions and truncating variants occurred throughout SOX5. In contrast, most missense variants clustered in the pivotal SOX-specific high-mobility-group domain. The latter variants prevented SOX5 from binding DNA and promoting transactivation in vitro, whereas missense variants located outside the high-mobility-group domain did not. Clinical manifestations and severity varied among patients. No clear genotype-phenotype correlations were found, except that missense variants outside the high-mobility-group domain were generally better tolerated.

Conclusions: This study extends the clinical and genetic spectrum associated with LAMSHF and consolidates evidence that SOX5 haploinsufficiency leads to variable degrees of intellectual disability, language delay, and other clinical features.
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http://dx.doi.org/10.1038/s41436-019-0657-0DOI Listing
March 2020

Expanding the Spectrum of BAF-Related Disorders: De Novo Variants in SMARCC2 Cause a Syndrome with Intellectual Disability and Developmental Delay.

Am J Hum Genet 2019 01 20;104(1):164-178. Epub 2018 Dec 20.

Department of Clinical Genetics, Erasmus Medical Center, 3015 GD Rotterdam, the Netherlands.

SMARCC2 (BAF170) is one of the invariable core subunits of the ATP-dependent chromatin remodeling BAF (BRG1-associated factor) complex and plays a crucial role in embryogenesis and corticogenesis. Pathogenic variants in genes encoding other components of the BAF complex have been associated with intellectual disability syndromes. Despite its significant biological role, variants in SMARCC2 have not been directly associated with human disease previously. Using whole-exome sequencing and a web-based gene-matching program, we identified 15 individuals with variable degrees of neurodevelopmental delay and growth retardation harboring one of 13 heterozygous variants in SMARCC2, most of them novel and proven de novo. The clinical presentation overlaps with intellectual disability syndromes associated with other BAF subunits, such as Coffin-Siris and Nicolaides-Baraitser syndromes and includes prominent speech impairment, hypotonia, feeding difficulties, behavioral abnormalities, and dysmorphic features such as hypertrichosis, thick eyebrows, thin upper lip vermilion, and upturned nose. Nine out of the fifteen individuals harbor variants in the highly conserved SMARCC2 DNA-interacting domains (SANT and SWIRM) and present with a more severe phenotype. Two of these individuals present cardiac abnormalities. Transcriptomic analysis of fibroblasts from affected individuals highlights a group of differentially expressed genes with possible roles in regulation of neuronal development and function, namely H19, SCRG1, RELN, and CACNB4. Our findings suggest a novel SMARCC2-related syndrome that overlaps with neurodevelopmental disorders associated with variants in BAF-complex subunits.
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http://dx.doi.org/10.1016/j.ajhg.2018.11.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6323608PMC
January 2019

Atypical Alexander disease with dystonia, retinopathy, and a brain mass mimicking astrocytoma.

Neurol Genet 2018 Aug 20;4(4):e248. Epub 2018 Jul 20.

Department of Molecular and Human Genetics (K.M., L.C.B., M.J., R.A.L., M.X., J.A.R., R.C., C.M.E., Y.Y., B.H.L., P.M.M., S.U.D.), Department of Neurology (J.J., D.V., P.M.M), and Department of Ophthalmology (R.A.L.), Baylor College of Medicine; Department of Pathology (G.N.F.), Department of Neuro-Oncology (M.P.-P.), and Department of Diagnostic Imaging (M.K.G.-M.), The University of Texas MD Anderson Cancer Center; Michael E. DeBakey VA Medical Center (P.M.M.); Baylor Genetics (C.M.E., Y.Y.); and Department of Medicine (S.U.D.), Baylor College of Medicine, Houston, TX.

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http://dx.doi.org/10.1212/NXG.0000000000000248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6055357PMC
August 2018

Corner fracture type spondylometaphyseal dysplasia: Overlap with type II collagenopathies.

Am J Med Genet A 2017 Mar 26;173(3):733-739. Epub 2016 Nov 26.

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.

Spondylometaphyseal dysplasia (SMD) corner fracture type (also known as SMD "Sutcliffe" type, MIM 184255) is a rare skeletal dysplasia that presents with mild to moderate short stature, developmental coxa vara, mild platyspondyly, corner fracture-like lesions, and metaphyseal abnormalities with sparing of the epiphyses. The molecular basis for this disorder has yet to be clarified. We describe two patients with SMD corner fracture type and heterozygous pathogenic variants in COL2A1. These two cases together with a third case of SMD corner fracture type with a heterozygous COL2A1 pathogenic variant previously described suggest that this disorder overlaps with type II collagenopathies. The finding of one of the pathogenic variants in a previously reported case of spondyloepimetaphyseal dysplasia (SEMD) Strudwick type and the significant clinical similarity suggest an overlap between SMD corner fracture and SEMD Strudwick types. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ajmg.a.38059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315610PMC
March 2017

De Novo Mutations in CHD4, an ATP-Dependent Chromatin Remodeler Gene, Cause an Intellectual Disability Syndrome with Distinctive Dysmorphisms.

Am J Hum Genet 2016 Oct 8;99(4):934-941. Epub 2016 Sep 8.

Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA. Electronic address:

Chromodomain helicase DNA-binding protein 4 (CHD4) is an ATP-dependent chromatin remodeler involved in epigenetic regulation of gene transcription, DNA repair, and cell cycle progression. Also known as Mi2β, CHD4 is an integral subunit of a well-characterized histone deacetylase complex. Here we report five individuals with de novo missense substitutions in CHD4 identified through whole-exome sequencing and web-based gene matching. These individuals have overlapping phenotypes including developmental delay, intellectual disability, hearing loss, macrocephaly, distinct facial dysmorphisms, palatal abnormalities, ventriculomegaly, and hypogonadism as well as additional findings such as bone fusions. The variants, c.3380G>A (p.Arg1127Gln), c.3443G>T (p.Trp1148Leu), c.3518G>T (p.Arg1173Leu), and c.3008G>A, (p.Gly1003Asp) (GenBank: NM_001273.3), affect evolutionarily highly conserved residues and are predicted to be deleterious. Previous studies in yeast showed the equivalent Arg1127 and Trp1148 residues to be crucial for SNF2 function. Furthermore, mutations in the same positions were reported in malignant tumors, and a de novo missense substitution in an equivalent arginine residue in the C-terminal helicase domain of SMARCA4 is associated with Coffin Siris syndrome. Cell-based studies of the p.Arg1127Gln and p.Arg1173Leu mutants demonstrate normal localization to the nucleus and HDAC1 interaction. Based on these findings, the mutations potentially alter the complex activity but not its formation. This report provides evidence for the role of CHD4 in human development and expands an increasingly recognized group of Mendelian disorders involving chromatin remodeling and modification.
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http://dx.doi.org/10.1016/j.ajhg.2016.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5065651PMC
October 2016

Corneal clouding, cataract, and colobomas with a novel missense mutation in B4GALT7-a review of eye anomalies in the linkeropathy syndromes.

Am J Med Genet A 2016 10 20;170(10):2711-8. Epub 2016 Jun 20.

Division of Genetics, Department of Pediatrics, University of California, San Francisco, California.

We present a 5-year-old female with a distinctive phenotype comprising global developmental delays, pre- and post-natal growth restriction, striking joint laxity with soft skin, and scoliosis. She had a triangular facies, a prominent forehead, proptosis, a small nose, and a small jaw. Her ocular findings included corneal clouding, colobomas of the iris and optic nerve, and posterior subcapsular cataracts. Exome sequencing identified homozygosity for c.970T>A, predicting p.(Cys324Ser), in the xylosylprotein 4-beta-galactosyltransferase, polypeptide 7 (B4GALT7) gene. Variant segregation was consistent with autosomal recessive inheritance and the missense substitution was predicted to be pathogenic. As the phenotype of this child is consistent with that described in other "linkeropathy" syndromes, we conclude that p.(Cys324Ser) is likely to be disease-causing. The eye features were a notable part of this child's presentation and mutations in the linkeropathy genes (XYLT1, XYLT2, B4GALT7, B3GALT6, and B3GAT3) can be associated with ocular findings, including blue sclerae, refractive errors, corneal clouding, strabismus, nystagmus, cataracts, glaucoma, and retinal abnormalities, including retinal detachment. The corneal clouding and cataracts in this patient may thus have been caused by her B4GALT7 mutation, but the colobomas are a novel phenotypic finding. However, a different genetic etiology or a role for modifying genetic factors has not been excluded in the etiology of her colobomas. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ajmg.a.37809DOI Listing
October 2016

Behçet's disease and cerebral sinus vein thrombosis in children: a case study and review of the literature.

Clin Exp Rheumatol 2015 Nov-Dec;33(6 Suppl 94):S163-8. Epub 2015 Oct 20.

Department of Paediatrics, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem, Israel.

Objectives: Central nervous system (CNS) involvement, one of the most severe manifestations of Behçet's disease (BD), is uncommon in children. Because it is rare, the clinical features of this disease in children are not well characterised. Here we describe a teenager with BD which was disclosed following an episode of cerebral sinus vein thrombosis (CSVT) and review the available literature on children with CSVT associated with BD.

Methods: A 12-year-old boy who presented with CSVT is described and the relevant literature, based on a Medline search from 1966 to January 2015 is reviewed.

Results: Twenty-three well-documented reports of children with CSVT and BD are described. This manifestation affected mainly males (61%) with a mean age of 12 years (range 4-18). BD was first diagnosed simultaneously or following CSVT in the majority of cases (75%). Multiple sinuses were involved in 30% of the cases. Thrombosis of additional large vessel was identified in 5 of the 23 children. The most common presenting symptom and signs were headache (91%), lasting more than 3 days in most cases (75%), followed by papilledema (43%), seizures (17%), and personality changes (9%). A mixed pattern of CNS involvement including both parenchymal involvement and CSVT, was demonstrated in only two patients (9%). Management of CSVT differed between reports.

Conclusions: CSVT in children is a rarely reported manifestation of BD and has a characteristic clinical picture of a teenage boy presenting with prolonged headache, with no previous diagnosis of BD. A therapeutic approach has not been established yet.
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January 2016

Keeping the heart in mind when managing hemolytic: uremic syndrome.

Isr Med Assoc J 2011 Jul;13(7):446-7

Department of Pediatric Critical Care Medicine, Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, affiliated with Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel.

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July 2011

The proto-oncogene ERG in megakaryoblastic leukemias.

Cancer Res 2005 Sep;65(17):7596-602

Department of Pediatric Hematology-Oncology, Safra Children's Hospital and Hematology Institute, Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel.

Aneuploidy is one of the hallmarks of cancer. Acquired additions of chromosome 21 are a common finding in leukemias, suggesting a contributory role to leukemogenesis. About 10% of patients with a germ line trisomy 21 (Down syndrome) are born with transient megakaryoblastic leukemia. We and others have shown acquired mutations in the X chromosome gene GATA1 in all these cases. The gene or genes on chromosome 21 whose overexpression promote the megakaryoblastic phenotype are presently unknown. We propose that ERG, an Ets transcription factor situated on chromosome 21, is one such candidate. We show that ERG is expressed in hematopoietic stem cells, megakaryoblastic cell lines, and in primary leukemic cells from Down syndrome patients. ERG expression is induced upon megakaryocytic differentiation of the erythroleukemia cell lines K562 and UT-7, and forced expression of ERG in K562 cells induces erythroid to megakaryoblastic phenotypic switch. We also show that ERG activates the gpIb megakaryocytic promoter and binds the gpIIb promoter in vivo. Furthermore, both ERG and ETS2 bind in vivo the hematopoietic enhancer of SCL/TAL1, a key regulator of hematopoietic stem cell and megakaryocytic development. We propose that trisomy 21 facilitates the occurrence of megakaryoblastic leukemias through a shift toward the megakaryoblastic lineage caused by the excess expression of ERG, and possibly by other chromosome 21 genes, such as RUNX1 and ETS2, in hematopoietic progenitor cells, coupled with a differentiation arrest caused by the acquisition of mutations in GATA1.
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http://dx.doi.org/10.1158/0008-5472.CAN-05-0147DOI Listing
September 2005
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