Publications by authors named "Karin Weiss"

29 Publications

  • Page 1 of 1

SPEN haploinsufficiency causes a neurodevelopmental disorder overlapping proximal 1p36 deletion syndrome with an episignature of X chromosomes in females.

Authors:
Francesca Clementina Radio Kaifang Pang Andrea Ciolfi Michael A Levy Andrés Hernández-García Lucia Pedace Francesca Pantaleoni Zhandong Liu Elke de Boer Adam Jackson Alessandro Bruselles Haley McConkey Emilia Stellacci Stefania Lo Cicero Marialetizia Motta Rosalba Carrozzo Maria Lisa Dentici Kirsty McWalter Megha Desai Kristin G Monaghan Aida Telegrafi Christophe Philippe Antonio Vitobello Margaret Au Katheryn Grand Pedro A Sanchez-Lara Joanne Baez Kristin Lindstrom Peggy Kulch Jessica Sebastian Suneeta Madan-Khetarpal Chelsea Roadhouse Jennifer J MacKenzie Berrin Monteleone Carol J Saunders July K Jean Cuevas Laura Cross Dihong Zhou Taila Hartley Sarah L Sawyer Fabíola Paoli Monteiro Tania Vertemati Secches Fernando Kok Laura E Schultz-Rogers Erica L Macke Eva Morava Eric W Klee Jennifer Kemppainen Maria Iascone Angelo Selicorni Romano Tenconi David J Amor Lynn Pais Lyndon Gallacher Peter D Turnpenny Karen Stals Sian Ellard Sara Cabet Gaetan Lesca Joset Pascal Katharina Steindl Sarit Ravid Karin Weiss Alison M R Castle Melissa T Carter Louisa Kalsner Bert B A de Vries Bregje W van Bon Marijke R Wevers Rolph Pfundt Alexander P A Stegmann Bronwyn Kerr Helen M Kingston Kate E Chandler Willow Sheehan Abdallah F Elias Deepali N Shinde Meghan C Towne Nathaniel H Robin Dana Goodloe Adeline Vanderver Omar Sherbini Krista Bluske R Tanner Hagelstrom Caterina Zanus Flavio Faletra Luciana Musante Evangeline C Kurtz-Nelson Rachel K Earl Britt-Marie Anderlid Gilles Morin Marjon van Slegtenhorst Karin E M Diderich Alice S Brooks Joost Gribnau Ruben G Boers Teresa Robert Finestra Lauren B Carter Anita Rauch Paolo Gasparini Kym M Boycott Tahsin Stefan Barakat John M Graham Laurence Faivre Siddharth Banka Tianyun Wang Evan E Eichler Manuela Priolo Bruno Dallapiccola Lisenka E L M Vissers Bekim Sadikovic Daryl A Scott Jimmy Lloyd Holder Marco Tartaglia

Am J Hum Genet 2021 Feb 9. Epub 2021 Feb 9.

Genetics and Rare Disease Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy. Electronic address:

Deletion 1p36 (del1p36) syndrome is the most common human disorder resulting from a terminal autosomal deletion. This condition is molecularly and clinically heterogeneous. Deletions involving two non-overlapping regions, known as the distal (telomeric) and proximal (centromeric) critical regions, are sufficient to cause the majority of the recurrent clinical features, although with different facial features and dysmorphisms. SPEN encodes a transcriptional repressor commonly deleted in proximal del1p36 syndrome and is located centromeric to the proximal 1p36 critical region. Here, we used clinical data from 34 individuals with truncating variants in SPEN to define a neurodevelopmental disorder presenting with features that overlap considerably with those of proximal del1p36 syndrome. The clinical profile of this disease includes developmental delay/intellectual disability, autism spectrum disorder, anxiety, aggressive behavior, attention deficit disorder, hypotonia, brain and spine anomalies, congenital heart defects, high/narrow palate, facial dysmorphisms, and obesity/increased BMI, especially in females. SPEN also emerges as a relevant gene for del1p36 syndrome by co-expression analyses. Finally, we show that haploinsufficiency of SPEN is associated with a distinctive DNA methylation episignature of the X chromosome in affected females, providing further evidence of a specific contribution of the protein to the epigenetic control of this chromosome, and a paradigm of an X chromosome-specific episignature that classifies syndromic traits. We conclude that SPEN is required for multiple developmental processes and SPEN haploinsufficiency is a major contributor to a disorder associated with deletions centromeric to the previously established 1p36 critical regions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2021.01.015DOI Listing
February 2021

Gene Haploinsufficiency in Three Patients With Suspected KBG Syndrome.

Front Neurol 2020 24;11:631. Epub 2020 Jul 24.

Research Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Milan, Italy.

Mendelian disorders of the epigenetic machinery (MDEMs), also named chromatin modifying disorders, are a broad group of neurodevelopmental disorders, caused by mutations in functionally related chromatin genes. Mental retardation autosomal dominant 23 (MRD23) syndrome, due to gene mutations, falls into this group of disorders. KBG syndrome, caused by gene haploinsufficiency, is a chromatin related syndrome not formally belonging to this category. We performed high resolution array CGH and trio-based WES on three molecularly unsolved patients with an initial KBGS clinical diagnosis. A deletion of 116 kb partially involving and two frameshift variants in were identified in the patients. The clinical re-evaluation of the patients was consistent with the molecular findings, though still compatible with KBGS due to overlapping phenotypic features of KBGS and MRD23. Careful detailed expert phenotyping ascertained some facial and physical features that were consistent with MRD23 rather than KBGS. Our results provide further examples that loss-of-function pathogenic variants in genes encoding factors shaping the epigenetic landscape, lead to a wide phenotypic range with significant clinical overlap. We recommend that clinicians consider gene haploinsufficiency in the differential diagnosis of KBGS. Due to overlap of clinical features, careful and detailed phenotyping is important and a large gene panel approach is recommended in the diagnostic workup of patients with a clinical suspicion of KBGS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fneur.2020.00631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7393934PMC
July 2020

De Novo Variants in the ATPase Module of MORC2 Cause a Neurodevelopmental Disorder with Growth Retardation and Variable Craniofacial Dysmorphism.

Am J Hum Genet 2020 08 20;107(2):352-363. Epub 2020 Jul 20.

GeneDx, Inc., Gaithersburg, MD 20877, USA.

MORC2 encodes an ATPase that plays a role in chromatin remodeling, DNA repair, and transcriptional regulation. Heterozygous variants in MORC2 have been reported in individuals with autosomal-dominant Charcot-Marie-Tooth disease type 2Z and spinal muscular atrophy, and the onset of symptoms ranges from infancy to the second decade of life. Here, we present a cohort of 20 individuals referred for exome sequencing who harbor pathogenic variants in the ATPase module of MORC2. Individuals presented with a similar phenotype consisting of developmental delay, intellectual disability, growth retardation, microcephaly, and variable craniofacial dysmorphism. Weakness, hyporeflexia, and electrophysiologic abnormalities suggestive of neuropathy were frequently observed but were not the predominant feature. Five of 18 individuals for whom brain imaging was available had lesions reminiscent of those observed in Leigh syndrome, and five of six individuals who had dilated eye exams had retinal pigmentary abnormalities. Functional assays revealed that these MORC2 variants result in hyperactivation of epigenetic silencing by the HUSH complex, supporting their pathogenicity. The described set of morphological, growth, developmental, and neurological findings and medical concerns expands the spectrum of genetic disorders resulting from pathogenic variants in MORC2.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2020.06.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413887PMC
August 2020

De Novo Variants in CNOT1, a Central Component of the CCR4-NOT Complex Involved in Gene Expression and RNA and Protein Stability, Cause Neurodevelopmental Delay.

Am J Hum Genet 2020 07 17;107(1):164-172. Epub 2020 Jun 17.

Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, the Netherlands.

CNOT1 is a member of the CCR4-NOT complex, which is a master regulator, orchestrating gene expression, RNA deadenylation, and protein ubiquitination. We report on 39 individuals with heterozygous de novo CNOT1 variants, including missense, splice site, and nonsense variants, who present with a clinical spectrum of intellectual disability, motor delay, speech delay, seizures, hypotonia, and behavioral problems. To link CNOT1 dysfunction to the neurodevelopmental phenotype observed, we generated variant-specific Drosophila models, which showed learning and memory defects upon CNOT1 knockdown. Introduction of human wild-type CNOT1 was able to rescue this phenotype, whereas mutants could not or only partially, supporting our hypothesis that CNOT1 impairment results in neurodevelopmental delay. Furthermore, the genetic interaction with autism-spectrum genes, such as ASH1L, DYRK1A, MED13, and SHANK3, was impaired in our Drosophila models. Molecular characterization of CNOT1 variants revealed normal CNOT1 expression levels, with both mutant and wild-type alleles expressed at similar levels. Analysis of protein-protein interactions with other members indicated that the CCR4-NOT complex remained intact. An integrated omics approach of patient-derived genomics and transcriptomics data suggested only minimal effects on endonucleolytic nonsense-mediated mRNA decay components, suggesting that de novo CNOT1 variants are likely haploinsufficient hypomorph or neomorph, rather than dominant negative. In summary, we provide strong evidence that de novo CNOT1 variants cause neurodevelopmental delay with a wide range of additional co-morbidities. Whereas the underlying pathophysiological mechanism warrants further analysis, our data demonstrate an essential and central role of the CCR4-NOT complex in human brain development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2020.05.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7332645PMC
July 2020

A second cohort of CHD3 patients expands the molecular mechanisms known to cause Snijders Blok-Campeau syndrome.

Eur J Hum Genet 2020 10 1;28(10):1422-1431. Epub 2020 Jun 1.

Children's Hospital of Philadelphia, Philadelphia, PA, USA.

There has been one previous report of a cohort of patients with variants in Chromodomain Helicase DNA-binding 3 (CHD3), now recognized as Snijders Blok-Campeau syndrome. However, with only three previously-reported patients with variants outside the ATPase/helicase domain, it was unclear if variants outside of this domain caused a clinically similar phenotype. We have analyzed 24 new patients with CHD3 variants, including nine outside the ATPase/helicase domain. All patients were detected with unbiased molecular genetic methods. There is not a significant difference in the clinical or facial features of patients with variants in or outside this domain. These additional patients further expand the clinical and molecular data associated with CHD3 variants. Importantly we conclude that there is not a significant difference in the phenotypic features of patients with various molecular disruptions, including whole gene deletions and duplications, and missense variants outside the ATPase/helicase domain. This data will aid both clinical geneticists and molecular geneticists in the diagnosis of this emerging syndrome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41431-020-0654-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608102PMC
October 2020

Deficiency of MFSD7c results in microcephaly-associated vasculopathy in Fowler syndrome.

J Clin Invest 2020 08;130(8):4081-4093

Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.

Several missense mutations in the orphan transporter FLVCR2 have been reported in Fowler syndrome. Affected subjects exhibit signs of severe neurological defects. We identified the mouse ortholog Mfsd7c as a gene expressed in the blood-brain barrier. Here, we report the characterizations of Mfsd7c-KO mice and compare these characterizations to phenotypic findings in humans with biallelic FLVCR2 mutations. Global KO of Mfsd7c in mice resulted in late-gestation lethality, likely due to CNS phenotypes. We found that the angiogenic growth of CNS blood vessels in the brain of Mfsd7c-KO embryos was inhibited in cortical ventricular zones and ganglionic eminences. Vascular tips were dilated and fused, resulting in glomeruloid vessels. Nonetheless, CNS blood vessels were intact, without hemorrhage. Both embryos and humans with biallelic FLVCR2 mutations exhibited reduced cerebral cortical layers, enlargement of the cerebral ventricles, and microcephaly. Transcriptomic analysis of Mfsd7cK-KO embryonic brains revealed upregulation of genes involved in glycolysis and angiogenesis. The Mfsd7c-KO brain exhibited hypoxia and neuronal cell death. Our results indicate that MFSD7c is required for the normal growth of CNS blood vessels and that ablation of this gene results in microcephaly-associated vasculopathy in mice and humans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/JCI136727DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7410059PMC
August 2020

The CHD4-related syndrome: a comprehensive investigation of the clinical spectrum, genotype-phenotype correlations, and molecular basis.

Genet Med 2020 02 7;22(2):389-397. Epub 2019 Aug 7.

Wessex Clinical Genetics Service, University Hospital Southampton NHS Trust. Department of Human Genetics and Genomic Medicine, Southampton University, Southampton, UK.

Purpose: Sifrim-Hitz-Weiss syndrome (SIHIWES) is a recently described multisystemic neurodevelopmental disorder caused by de novo variants inCHD4. In this study, we investigated the clinical spectrum of the disorder, genotype-phenotype correlations, and the effect of different missense variants on CHD4 function.

Methods: We collected clinical and molecular data from 32 individuals with mostly de novo variants in CHD4, identified through next-generation sequencing. We performed adenosine triphosphate (ATP) hydrolysis and nucleosome remodeling assays on variants from five different CHD4 domains.

Results: The majority of participants had global developmental delay, mild to moderate intellectual disability, brain anomalies, congenital heart defects, and dysmorphic features. Macrocephaly was a frequent but not universal finding. Additional common abnormalities included hypogonadism in males, skeletal and limb anomalies, hearing impairment, and ophthalmic abnormalities. The majority of variants were nontruncating and affected the SNF2-like region of the protein. We did not identify genotype-phenotype correlations based on the type or location of variants. Alterations in ATP hydrolysis and chromatin remodeling activities were observed in variants from different domains.

Conclusion: The CHD4-related syndrome is a multisystemic neurodevelopmental disorder. Missense substitutions in different protein domains alter CHD4 function in a variant-specific manner, but result in a similar phenotype in humans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-019-0612-0DOI Listing
February 2020

Cohesin complex-associated holoprosencephaly.

Brain 2019 09;142(9):2631-2643

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.

Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven research, 80-90% of aneuploidy-negative holoprosencephaly individuals with a probable genetic aetiology do not have a genetic diagnosis. Here we report holoprosencephaly associated with variants in the two X-linked cohesin complex genes, STAG2 and SMC1A, with loss-of-function variants in 10 individuals and a missense variant in one. Additionally, we report four individuals with variants in the cohesin complex genes that are not X-linked, SMC3 and RAD21. Using whole mount in situ hybridization, we show that STAG2 and SMC1A are expressed in the prosencephalic neural folds during primary neurulation in the mouse, consistent with forebrain morphogenesis and holoprosencephaly pathogenesis. Finally, we found that shRNA knockdown of STAG2 and SMC1A causes aberrant expression of HPE-associated genes ZIC2, GLI2, SMAD3 and FGFR1 in human neural stem cells. These findings show the cohesin complex as an important regulator of median forebrain development and X-linked inheritance patterns in holoprosencephaly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awz210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245359PMC
September 2019

A CCR4-NOT Transcription Complex, Subunit 1, CNOT1, Variant Associated with Holoprosencephaly.

Am J Hum Genet 2019 05 18;104(5):990-993. Epub 2019 Apr 18.

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

Holoprosencephaly is the incomplete separation of the forebrain during embryogenesis. Both genetic and environmental etiologies have been determined for holoprosencephaly; however, a genetic etiology is not found in most cases. In this report, we present two unrelated individuals with semilobar holoprosencephaly who have the identical de novo missense variant in the gene CCR4-NOT transcription complex, subunit 1 (CNOT1). The variant (c.1603C>T [p.Arg535Cys]) is predicted to be deleterious and is not present in public databases. CNOT1 has not been previously associated with holoprosencephaly or other brain malformations. In situ hybridization analyses of mouse embryos show that Cnot1 is expressed in the prosencephalic neural folds at gestational day 8.25 during the critical period for subsequent forebrain division. Combining human and mouse data, we show that CNOT1 is associated with incomplete forebrain division.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2019.03.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6506867PMC
May 2019

Identification of a novel PCNT founder pathogenic variant in the Israeli Druze population.

Eur J Med Genet 2020 Feb 25;63(2):103643. Epub 2019 Mar 25.

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA.

Majewski Osteodysplastic Primordial Dwarfism type II (MOPDII) is a form of dwarfism associated with severe microcephaly, characteristic skeletal findings, distinct dysmorphic features and increased risk for cerebral infarctions. The condition is caused by bi-allelic loss-of-function variants in the gene PCNT. Here we describe the identification of a novel founder pathogenic variant c.3465-1G > A observed in carriers from multiple Druze villages in Northern Israel. RNA studies show that the variant results in activation of a cryptic splice site causing a coding frameshift. The study was triggered by the diagnosis of a single child with MOPDII and emphasizes the advantages of applying next generation sequencing technologies in community genetics and the importance of establishing population-specific sequencing databases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmg.2019.03.007DOI Listing
February 2020

Holoprosencephaly from conception to adulthood.

Am J Med Genet C Semin Med Genet 2018 06;178(2):122-127

National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.

Holoprosencephaly (HPE) consists of a spectrum of malformations related to incomplete separation of the prosencephalon. There is a wide clinical variability depending on the HPE subtype seen on imaging. Early postnatal lethality is common, however a significant fraction of newborns diagnosed with HPE will survive into childhood and even adulthood. Here we will review the clinical management of HPE during different ages from the prenatal period to adulthood.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.c.31624DOI Listing
June 2018

Rare Disease Diagnostics: A Single-center Experience and Lessons Learnt.

Rambam Maimonides Med J 2018 Jul 30;9(3). Epub 2018 Jul 30.

The Genetics Institute, Rambam Health Care Center, Haifa, Israel.

Objective: The growing availability of next-generation sequencing technologies has revolutionized medical genetics, facilitating discovery of causative genes in numerous Mendelian disorders. Nevertheless, there are still many undiagnosed cases. We report the experience of the Genetics Institute at Rambam Health Care Campus in rare disease diagnostics using whole-exome sequencing (WES).

Methods: Phenotypic characterization of patients was done in close collaboration with referring physicians. We utilized WES analysis for diagnosing families suspected for rare genetic disorders. Bioinformatic analysis was performed in-house using the Genoox analysis platform.

Results: Between the years 2014 and 2017, we studied 34 families. Neurological manifestations were the most common reason for referral (38%), and 55% of families were consanguineous. A definite diagnosis was reached in 21 cases (62%). Four cases (19%) were diagnosed with variants in novel genes. In addition, six families (18%) had strong candidate novel gene discoveries still under investigation. Therefore, the true diagnosis rate is probably even higher. Some of the diagnoses had a significant impact such as alerting the patient management and providing a tailored treatment.

Conclusions: An accurate molecular diagnosis can set the stage for improved patient care and provides an opportunity to study disease mechanisms, which may lead to development of tailored treatments. Data from our genetic research program demonstrate high diagnostic and novel disease-associated or causative gene discovery rates. This is likely related to the unique genetic architecture of the population in Northern Israel as well as to our strategy for case selection and the close collaboration between analysts, geneticists, and clinicians, all working in the same hospital.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5041/RMMJ.10341DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6115477PMC
July 2018

Refugees in Europe: national overviews from key countries with a special focus on child and adolescent mental health.

Eur Child Adolesc Psychiatry 2018 Apr;27(4):389-399

Centre for Child and Adolescent Mental Health and Child Protection, Institute of Psychiatry, Norwegian University of Science and Technology (NTNU), Klostergata 46, 7030, Trondheim, Norway.

Many European countries are becoming multicultural at a previously unseen rate. The number of immigrants including refugees has considerably increased since 2008, and especially after the beginning of the war in Syria. In 2015, 88,300 unaccompanied minors sought asylum in the Member States of the European Union (EU) and most came from Syria, Afghanistan, Iran, Iraq, Somalia and Eritrea. As a reaction to increased immigration, governments in many countries including Germany, Sweden and Norway implemented more restrictive immigration policy. A requirement for all countries, however, is the protection and welfare provision for all arriving children, regardless of their nationality, ensured by international and national legal frameworks. This paper provides an overview of the post 2015 immigration crisis in key European countries with a special focus on current demographics, refugee children, mental health studies, policies and practical support available for refugees.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00787-017-1094-8DOI Listing
April 2018

SIX3 deletions and incomplete penetrance in families affected by holoprosencephaly.

Congenit Anom (Kyoto) 2018 Jan 1;58(1):29-32. Epub 2017 Aug 1.

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.

Holoprosencephaly (HPE) is failure of the forebrain to divide completely during embryogenesis. Incomplete penetrance has not been reported previously in SIX3 whole gene deletions, which are known to cause HPE. Both chromosomal microarray and whole exome sequencing (WES) were used to evaluate families with inherited HPE. Two families showed inherited deletions that contain SIX3 and were incompletely penetrant for HPE. Using WES, we ruled out parental mosaicism, a SIX3 hypomorph, and clinically significant variants in genes that are known to interact with SIX3 as causes of incomplete penetrance. We demonstrate the importance of molecular cascade testing in families with HPE and we answer important questions about incomplete penetrance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cga.12234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5750110PMC
January 2018

Human germline hedgehog pathway mutations predispose to fatty liver.

J Hepatol 2017 10 21;67(4):809-817. Epub 2017 Jun 21.

National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States. Electronic address:

Background & Aims: Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease. Activation of hedgehog (Hh) signaling has been implicated in the progression of NAFLD and proposed as a therapeutic target; however, the effects of Hh signaling inhibition have not been studied in humans with germline mutations that affect this pathway.

Methods: Patients with holoprosencephaly (HPE), a disorder associated with germline mutations disrupting Sonic hedgehog (SHH) signaling, were clinically evaluated for NAFLD. A combined mouse model of Hh signaling attenuation (Gli2 heterozygous null: Gli2) and diet-induced NAFLD was used to examine aspects of NAFLD and hepatic gene expression profiles, including molecular markers of hepatic fibrosis and inflammation.

Results: Patients with HPE had a higher prevalence of liver steatosis compared to the general population, independent of obesity. Exposure of Gli2 mice to fatty liver-inducing diets resulted in increased liver steatosis compared to wild-type mice. Similar to humans, this effect was independent of obesity in the mutant mice and was associated with decreased expression of pro-fibrotic and pro-inflammatory genes, and increased expression of PPARγ, a potent anti-fibrogenic and anti-inflammatory regulator. Interestingly, tumor suppressors p53 and p16INK4 were found to be downregulated in the Gli2 mice exposed to a high-fat diet.

Conclusions: Our results indicate that germline mutations disrupting Hh signaling promotes liver steatosis, independent of obesity, with reduced fibrosis. While Hh signaling inhibition has been associated with a better NAFLD prognosis, further studies are required to evaluate the long-term effects of mutations affecting this pathway. Lay summary: Non-alcoholic fatty liver disease (NAFLD) is characterized by excess fat deposition in the liver predominantly due to high calorie intake and a sedentary lifestyle. NAFLD progression is usually accompanied by activation of the Sonic hedgehog (SHH) pathway leading to fibrous buildup (scar tissue) and inflammation of the liver tissue. For the first time patients with holoprosencephaly, a disease caused by SHH signaling mutations, are shown to have increased liver steatosis independent of obesity. This observation was recapitulated in a mouse model of attenuated SHH signaling that also showed increased liver steatosis but with decreased fibrosis and inflammation. While SHH inhibition is associated with a good NAFLD prognosis, this increase in liver fat accumulation in the context of SHH signaling inhibition must be studied prospectively to evaluate its long-term effects, especially in individuals with Western-type dietary habits.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhep.2017.06.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613974PMC
October 2017

In-depth investigations of adolescents and adults with holoprosencephaly identify unique characteristics.

Genet Med 2018 01 22;20(1):14-23. Epub 2017 Jun 22.

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.

PurposeWith improved medical care, some individuals with holoprosencephaly (HPE) are surviving into adulthood. We investigated the clinical manifestations of adolescents and adults with HPE and explored the underlying molecular causes.MethodsParticipants included 20 subjects 15 years of age and older. Clinical assessments included dysmorphology exams, cognitive testing, swallowing studies, ophthalmic examination, and brain magnetic resonance imaging. Genetic testing included chromosomal microarray, Sanger sequencing for SHH, ZIC2, SIX3, and TGIF, and whole-exome sequencing (WES) of 10 trios.ResultsSemilobar HPE was the most common subtype of HPE, seen in 50% of the participants. Neurodevelopmental disabilities were found to correlate with HPE subtype. Factors associated with long-term survival included HPE subtype not alobar, female gender, and nontypical facial features. Four participants had de novo pathogenic variants in ZIC2. WES analysis of 11 participants did not reveal plausible candidate genes, suggesting complex inheritance in these cases. Indeed, in two probands there was a history of uncontrolled maternal type 1 diabetes.ConclusionIndividuals with various HPE subtypes can survive into adulthood and the neurodevelopmental outcomes are variable. Based on the facial characteristics and molecular evaluations, we suggest that classic genetic causes of HPE may play a smaller role in this cohort.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/gim.2017.68DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5763157PMC
January 2018

Haploinsufficiency of ZNF462 is associated with craniofacial anomalies, corpus callosum dysgenesis, ptosis, and developmental delay.

Eur J Hum Genet 2017 08 17;25(8):946-951. Epub 2017 May 17.

Department of Medical Genetics, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.

The introduction of whole-exome sequencing into the Pediatric Genetics clinic has increased the identification of novel genes associated with neurodevelopmental disorders and congenital anomalies. This agnostic approach has shed light on multiple proteins and pathways not previously known to be associated with disease. Here we report eight subjects from six families with predicted loss of function variants in ZNF462, a zinc-finger protein of unknown function. These individuals have overlapping phenotypes that include ptosis, metopic ridging, craniosynostosis, dysgenesis of the corpus callosum, and developmental delay. We propose that ZNF462 plays an important role in embryonic development, and is associated with craniofacial and neurodevelopmental abnormalities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ejhg.2017.86DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5567153PMC
August 2017

KCNQ1 Gene Variants in Large Asymptomatic Populations: Considerations for Genomic Screening of Military Cohorts.

Mil Med 2017 03;182(3):e1795-e1800

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 35 Convent Drive, Room 1B207, Bethesda, MD 20894.

Introduction: The advances in genomic technology of large populations make the potential for genomic screening of military cohorts and recruits feasible, affording the potential to identify at-risk individuals before occurrence of potentially life-threatening events. Exploring sudden cardiac death, known to cause significant morbidity and mortality in young military service members, we focused on the most common gene associated with long QT syndrome (LQTS), KCNQ1.

Materials And Methods: Using the publicly available database Exome Aggregation Consortium as a surrogate for a military population, variants in KCNQ1 were filtered on the basis of population prevalence, classification as a disease mutation in the Human Gene Mutation database, and classification as pathogenic or likely pathogenic in the ClinVar database. Variant prevalence and penetrance estimates were derived using reports from the medical literature.

Results: We showed that in a population of over 60,000 individuals, at least 97 (0.2%) individuals would harbor a potentially pathogenic mutation in KCNQ1, which is more prevalent than expected on the basis of current medical literature (p = 0.0004). KCNQ1 variant penetrance was estimated to be only 9% to 17%. Identifying the importance of large genomic studies, our study demonstrates that 46% of pathogenic mutations in KCNQ1 had a population frequency of less than 1:50,000.

Conclusion: Screening a large database with genomic screening for a condition that is relevant to active duty service members results in the identification of many individuals with potentially pathogenic mutations in the KCNQ1 gene, which has profound implications for screening military or other adult cohorts in terms of over diagnosis, overtreatment, and increased medical resource usage. This study of KCNQ1 provides a platform for consideration of other genes that cause sudden cardiac death as well as other medically actionable hereditary disorders for which genomic screening is available. We review the potential benefits of genomic screening and also present the complex hurdles that will be encountered as such technologies unfold.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7205/MILMED-D-16-00184DOI Listing
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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2016.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5065651PMC
October 2016

Familial TAB2 microdeletion and congenital heart defects including unusual valve dysplasia and tetralogy of fallot.

Am J Med Genet A 2015 Nov 2;167A(11):2702-6. Epub 2015 Jul 2.

McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Haploinsufficiency of TAB2 was recently implicated as a cause for a variety of congenital heart defects. Reported cases have genomic deletions of 2-10 Mbs including TAB2 at 6q24-25 are almost always de novo and show variable cardiac and extra cardiac phenotype. We report on an inherited, 281 kb deletion in a three generation family. This is the smallest reported deletion involving TAB2 that segregates with congenital heart defects. Three affected individuals in this family present with myxomatous cardiac valves in addition to structural heart defects commonly associated with TAB2 deletions. Findings from this family support a key role of TAB2 haploinsufficiency in congenital heart defects and expand the phenotypic spectrum of TAB2-microdeletion syndrome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.37210DOI Listing
November 2015

The clinical management of Type 2 Gaucher disease.

Mol Genet Metab 2015 Feb 14;114(2):110-122. Epub 2014 Nov 14.

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.

Gaucher disease, the inherited deficiency of the enzyme glucocerebrosidase, is the most common of the lysosomal storage disorders. Type 2 Gaucher disease, the most severe and progressive form, manifests either prenatally or in the first months of life, followed by death within the first years of life. The rarity of the many lysosomal storage disorders makes their diagnosis a challenge, especially in the newborn period when the focus is often on more prevalent illnesses. Thus, a heightened awareness of the presentation of these rare diseases is necessary to ensure their timely consideration. This review, designed to serve as a guide to physicians treating newborns and infants with Gaucher disease, discusses the presenting manifestations of Type 2 Gaucher disease, the diagnostic work-up, associated genotypes and suggestions for management. We also address the ethical concerns that may arise with this progressive and lethal disorder, since currently available treatments may prolong life, but do not impact the neurological manifestations of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ymgme.2014.11.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4312716PMC
February 2015

Ethnic effect on FMR1 carrier rate and AGG repeat interruptions among Ashkenazi women.

Genet Med 2014 Dec 29;16(12):940-4. Epub 2014 May 29.

Genetic Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.

Purpose: Fragile X syndrome, a common cause of intellectual disability, is usually caused by CGG trinucleotide expansion in the FMR1 gene. CGG repeat size correlates with expansion risk. Premutation alleles (55-200 repeats) may expand to full mutations in female meiosis. Interspersed AGG repeats decrease allele instability and expansion risk. The carrier rate and stability of FMR1 alleles were evaluated in large cohorts of Ashkenazi and non-Ashkenazi women.

Methods: A total of 4,344 Ashkenazi and 4,985 non-Ashkenazi cases were analyzed using Southern blotting and polymerase chain reaction between 2004 and 2011. In addition, AGG interruptions were evaluated in 326 Ashkenazi and 298 non-Ashkenazi women who were recruited during 2011.

Results: Both groups had major peaks of 30 and 29 repeats. Ashkenazi women had a higher frequency of 30 repeats and a lower frequency of other peaks (P < 0.0001). A higher rate of premutations in the 55-59 repeats range (1:114 vs. 1:277) was detected among the Ashkenazi women. Loss of AGG interruptions (<2) was significantly less common among Ashkenazi women (9 vs. 19.5% for non-Ashkenazi women, P = 0.0002).

Conclusion: Ashkenazi women have a high fragile X syndrome carrier rate and mostly lower-range premutations, and carry a low risk for expansion to a full mutation. Normal-sized alleles in Ashkenazi women have higher average number of AGG interruptions that may increase stability. These factors may decrease the risk for fragile X syndrome offspring among Ashkenazi women.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/gim.2014.64DOI Listing
December 2014

How to evaluate the child presenting with an apparent life-threatening event?

Isr Med Assoc J 2010 Mar;12(3):154-7

Department of Pediatrics, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.

Background: Infants who have experienced an apparent life-threatening event typically undergo an extensive evaluation to rule out serious underlying conditions.

Objectives: To evaluate the yield of different tests performed after an apparent life-threatening event and to identify high risk groups in which more extensive diagnostic tests are required.

Methods: A retrospective study was conducted in a children's hospital for a 4 year period and the charts of infants who were admitted with an apparent life-threatening event were reviewed. The yield for each diagnostic test was established according to the ratio of positive results contributing to the diagnosis of the apparent life-threatening event.

Results: The study included 69 infants between the ages of 1 week and 1 year. There were abnormal findings in 36% of the cases. Gastroesophageal reflux was the most common diagnosis (60%). In the remaining patients the diagnosis was either seizures (12%) or respiratory tract infections (28%). Tests used for the diagnosis of cardiac, metabolic and nonrespiratory infections had no yield. A positive correlation was found between abnormal test results and abnormal physical examination (P = 0.001), an abnormal perinatal history (P = 0.017), and age older than 2 months (P = 0.002).

Conclusions: The yield of most of the tests performed after an apparent life-threatening event is low, especially in infants with a normal perinatal history and physical examination.
View Article and Find Full Text PDF

Download full-text PDF

Source
March 2010

Congenital myopathies in Israeli families.

J Child Neurol 2007 Jun;22(6):732-6

Sourasky Medical Center, Tel-Aviv, Isreal.

The clinical features of 37 patients from 32 Israeli families with congenital myopathies evaluated between 1983 and 2004 are described: 13 children were diagnosed with congenital fiber type disproportion, 10 had myotubular myopathy, 7 had nemaline myopathy, 5 had central core disease, 1 had actin myopathy, and 1 had multi-minicore disease. There were 7 families (22%) that had parental consanguinity, and 4 families (12%) had more than 1 patient with congenital myopathy. Of the patients, 31 (84%) presented with clinical symptoms before 4 months of age, and 6 children (16%) presented after 1 year of age. Thirteen children (35%) had a severe phenotype with chronic ventilatory dependence or mortality before the age of 11 years. Facial weakness was associated with a severe phenotype. There was a high rate of a severe clinical phenotype in patients with myotubular myopathy (60%) and in patients with nemaline myopathy (57%), whereas in patients with congenital fiber type disproportion and in patients with central core disease, the proportion of a severe phenotype was lower (23% and 0%, respectively).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0883073807304193DOI Listing
June 2007

Non-classical Kawasaki disease in a 2 month old infant.

Isr Med Assoc J 2006 Aug;8(8):581-2

Department of Pediatrics, Assaf Harofeh Medical Center, Zerifin, Israel.

View Article and Find Full Text PDF

Download full-text PDF

Source
August 2006

The ampakine CX546 restores the prepulse inhibition and latent inhibition deficits in mGluR5-deficient mice.

Neuropsychopharmacology 2007 Apr 23;32(4):745-56. Epub 2006 Aug 23.

Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.

In order to test the possible role of mGluR5 signaling in the behavioral endophenotypes of schizophrenia and other psychiatric disorders, we used genetic engineering to create mice carrying null mutations in this gene. Compared to their mGluR5(+/+) littermates, mGluR5(-/-) mice have disrupted latent inhibition (LI) as measured in a thirst-motivated conditioned emotional response procedure. Administration of the positive modulator of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors (AMPAR), CX546, during the conditioning phase only, improved the disrupted LI in mGluR5 knockout mice and facilitated LI in control C57BL/6J mice, given extended number of conditioning trails (four conditioning stimulus-unconditioned stimulus). Prepulse inhibition (PPI) was impaired in mGluR5(-/-) mice to a level that could not be disrupted further by the antagonist of N-methyl-D-aspartate receptors - MK-801. PPI deficit of mGluR5(-/-) mice was effectively reversed by CX546, whereas aniracetam had a less pronounced effect. These data provide evidence that a potent positive AMPAR modulator can elicit antipsychotic action and represents a new approach for treatment of schizophrenia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/sj.npp.1301191DOI Listing
April 2007

A genetic screen for mouse mutations with defects in serotonin responsiveness.

Brain Res Mol Brain Res 2003 Jul;115(2):162-72

Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5.

The serotonergic system plays a key role in regulating basic behaviors. Deficits in serotonergic neurotransmission have been implicated in psychiatric disorders, such as schizophrenia and depression. Here we have optimized a behavioral screen and performed a small scale genetic screen to identify genes involved in serotonin responsiveness in the mouse. Treatment of mice with serotonin, serotonin precursors, or serotonin agonists results in a quantifiable head twitch response (HTR), which is drug dosage-dependent and dependent on the 5-HT2A receptor system. This assay can uncover variation in serotonin responsiveness as shown by our identification of inbred strains with high, medium, and low head twitch responses to administration of the serotonin agonist DOI (+-1-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane). We chose C57Bl/6J mice for our mutagenesis screen, because of their robust HTR and because of the availability of their complete genomic sequence. We optimized this assay by examining dose and age dependence of DOI-induced HTR in 6-week and 3-month-old C57BL/6J mice. HTR decreases only slightly in 3-month-old mice, and a substantial but submaximal HTR is induced by 0.75-1 mg/kg of DOI. We assayed HTR in response to DOI of 247 G1 C57BL/6J progeny from C57BL/6J males, which had been mutagenized with ethylnitrososurea (ENU), and recovered one provisionally heritable hyper-responsive mutation. This and future mutations recovered via this protocol may provide ideal subjects for the study of human psychiatric disorders, such as depression and schizophrenia, and thereby aid in the development of better therapeutic strategies for these disorders. Thus, it is well worth expanding on this genetic screen in its current form and by addition of further pharmacologic assays in the future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/s0169-328x(03)00205-5DOI Listing
July 2003