ARF1-related disorder: phenotypic and molecular spectrum
de Sainte Agathe JM, Pode-Shakked B, Naudion S, Michaud V, Arveiler B, Fergelot P, Delmas J, Keren B, Poirsier C, Alkuraya FS, Tabarki B, Bend E, Davis K, Bebin M, Thompson ML, Bryant EM, Wagner M, Hannibal I, Lenberg J, Krenn M, Wigby KM, Friedman JR, Iascone M, Cereda A, Miao T, LeGuern E, Argilli E, Sherr E, Caluseriu O, Tidwell T, Bayrak-Toydemir P, Hagedorn C, Brugger M, Vill K, Morneau-Jacob FD, Chung W, Weaver KN, Owens JW, Husami A, Chaudhari BP, Stone BS, Burns K, Li R, de Lange IM, Biehler M, Ginglinger E, Gérard B, Stottmann RW, Trimouille A.
J Med Genet. 2023 Apr 25:jmg-2022-108803. doi: 10.1136/jmg-2022-108803. Online ahead of print.
PURPOSE: ARF1 was previously implicated in periventricular nodular heterotopia (PVNH) in only five individuals and systematic clinical characterisation was not available. The aim of this study is to provide a comprehensive description of the phenotypic and genotypic spectrum of ARF1-related neurodevelopmental disorder.
METHODS: We collected detailed phenotypes of an international cohort of individuals (n=17) with ARF1 variants assembled through the GeneMatcher platform. Missense variants were structurally modelled, and the impact of several were functionally validated.
RESULTS: De novo variants (10 missense, 1 frameshift, 1 splice altering resulting in 9 residues insertion) in ARF1 were identified among 17 unrelated individuals. Detailed phenotypes included intellectual disability (ID), microcephaly, seizures and PVNH. No specific facial characteristics were consistent across all cases, however microretrognathia was common. Various hearing and visual defects were recurrent, and interestingly, some inflammatory features were reported. MRI of the brain frequently showed abnormalities consistent with a neuronal migration disorder.
CONCLUSION: We confirm the role of ARF1 in an autosomal dominant syndrome with a phenotypic spectrum including severe ID, microcephaly, seizures and PVNH due to impaired neuronal migration.
April 25, 2023
Genetic Neurologic Disease
Transitional Care for Young People with Movement Disorders: Consensus-Based Recommendations from the MDS Task Force on Pediatrics
Pringsheim T, Batla A, Shalash A, Sahu JK, Cosentino C, Ebrahimi-Fakhari D, Friedman J, Lin JP, Mink J, Munchau A, Munoz D, Nardocci N, Perez-Dueñas B, Sardar Z, Triki C, Ben-Pazi H, Silveira-Moriyama L, Troncoso-Schifferli M, Hoshino K, Dale RC, Fung VSC, Kurian MA, Roze E.
Mov Disord Clin Pract. 2023 Apr 4;10(5):748-755. doi: 10.1002/mdc3.13728. eCollection 2023 May.
BACKGROUND: The International Parkinson and Movement Disorders Society (MDS) set up a working group on pediatric movement disorders (MDS Task Force on Pediatrics) to generate recommendations to guide the transition process from pediatrics to adult health care systems in patients with childhood-onset movement disorders.
METHODS: To develop recommendations for transitional care for childhood onset movement disorders, we used a formal consensus development process, using a multi-round, web-based Delphi survey. The Delphi survey was based on the results of the scoping review of the literature and the results of a survey of MDS members on transition practices. Through iterative discussions, we generated the recommendations included in the survey. The MDS Task Force on Pediatrics were the voting members for the Delphi survey. The task force members comprise 23 child and adult neurologists with expertise in the field of movement disorders and from all regions of the world.
RESULTS: Fifteen recommendations divided across four different areas were made pertaining to: (1) team composition and structure, (2) planning and readiness, (3) goals of care, and (4) administration and research. All recommendations achieved consensus with a median score of 7 or greater.
CONCLUSION: Recommendations on providing transitional care for patients with childhood onset movement disorders are provided. Nevertheless several challenges remain in the implementation of these recommendations, related to health infrastructure and the distribution of health resources, and the availability of knowledgeable and interested practitioners. Research on the influence of transitional care programs on outcomes in childhood onset movement disorders is much needed.
April 4, 2023
Genetic Neurologic Disease
Functional and clinical studies reveal pathophysiological complexity of CLCN4-related neurodevelopmental condition
Palmer EE, Pusch M, Picollo A, Forwood C, Nguyen MH, Suckow V, Gibbons J, Hoff A, Sigfrid L, Megarbane A, Nizon M, Cogné B, Beneteau C, Alkuraya FS, Chedrawi A, Hashem MO, Stamberger H, Weckhuysen S, Vanlander A, Ceulemans B, Rajagopalan S, Nunn K, Arpin S, Raynaud M, Motter CS, Ward-Melver C, Janssens K, Meuwissen M, Beysen D, Dikow N, Grimmel M, Haack TB, Clement E, McTague A, Hunt D, Townshend S, Ward M, Richards LJ, Simons C, Costain G, Dupuis L, Mendoza-Londono R, Dudding-Byth T, Boyle J, Saunders C, Fleming E, El Chehadeh S, Spitz MA, Piton A, Gerard B, Abi Warde MT, Rea G, McKenna C, Douzgou S, Banka S, Akman C, Bain JM, Sands TT, Wilson GN, Silvertooth EJ, Miller L, Lederer D, Sachdev R, Macintosh R, Monestier O, Karadurmus D, Collins F, Carter M, Rohena L, Willemsen MH, Ockeloen CW, Pfundt R, Kroft SD, Field M, Laranjeira FER, Fortuna AM, Soares AR, Michaud V, Naudion S, Golla S, Weaver DD, Bird LM, Friedman J, Clowes V, Joss S, Pölsler L, Campeau PM, Blazo M, Bijlsma EK, Rosenfeld JA, Beetz C, Powis Z, McWalter K, Brandt T, Torti E, Mathot M, Mohammad SS, Armstrong R, Kalscheuer VM.
Mol Psychiatry. 2022 Nov 16. doi: 10.1038/s41380-022-01852-9. Online ahead of print.
Missense and truncating variants in the X-chromosome-linked CLCN4 gene, resulting in reduced or complete loss-of-function (LOF) of the encoded chloride/proton exchanger ClC-4, were recently demonstrated to cause a neurocognitive phenotype in both males and females. Through international clinical matchmaking and interrogation of public variant databases we assembled a database of 90 rare CLCN4 missense variants in 90 families: 41 unique and 18 recurrent variants in 49 families. For 43 families, including 22 males and 33 females, we collated detailed clinical and segregation data. To confirm causality of variants and to obtain insight into disease mechanisms, we investigated the effect on electrophysiological properties of 59 of the variants in Xenopus oocytes using extended voltage and pH ranges. Detailed analyses revealed new pathophysiological mechanisms: 25% (15/59) of variants demonstrated LOF, characterized by a “shift” of the voltage-dependent activation to more positive voltages, and nine variants resulted in a toxic gain-of-function, associated with a disrupted gate allowing inward transport at negative voltages. Functional results were not always in line with in silico pathogenicity scores, highlighting the complexity of pathogenicity assessment for accurate genetic counselling. The complex neurocognitive and psychiatric manifestations of this condition, and hitherto under-recognized impacts on growth, gastrointestinal function, and motor control are discussed. Including published cases, we summarize features in 122 individuals from 67 families with CLCN4-related neurodevelopmental condition and suggest future research directions with the aim of improving the integrated care for individuals with this diagnosis.
November 16, 2022
Genetic Neurologic DiseaseNeurogenomics
De Novo ZMYND8 variants result in an autosomal dominant neurodevelopmental disorder with cardiac malformations
Dias KR, Carlston CM, Blok LER, De Hayr L, Nawaz U, Evans CA, Bayrak-Toydemir P, Htun S, Zhu Y, Ma A, Lynch SA, Moorwood C, Stals K, Ellard S, Bainbridge MN, Friedman J, Pappas JG, Rabin R, Nowak CB, Douglas J, Wilson TE, Guillen Sacoto MJ, Mullegama SV, Palculict TB, Kirk EP, Pinner JR, Edwards M, Montanari F, Graziano C, Pippucci T, Dingmann B, Glass I, Mefford HC, Shimoji T, Suzuki T, Yamakawa K, Streff H, Schaaf CP, Slavotinek AM, Voineagu I, Carey JC, Buckley MF, Schenck A, Harvey RJ, Roscioli T.
Genet Med. 2022 Aug 1:S1098-3600(22)00803-6. doi: 10.1016/j.gim.2022.06.001. Online ahead of print.
PURPOSE: ZMYND8 encodes a multidomain protein that serves as a central interactive hub for coordinating critical roles in transcription regulation, chromatin remodeling, regulation of super-enhancers, DNA damage response and tumor suppression. We delineate a novel neurocognitive disorder caused by variants in the ZMYND8 gene.
METHODS: An international collaboration, exome sequencing, molecular modeling, yeast two-hybrid assays, analysis of available transcriptomic data and a knockdown Drosophila model were used to characterize the ZMYND8 variants.
RESULTS: ZMYND8 variants were identified in 11 unrelated individuals; 10 occurred de novo and one suspected de novo; 2 were truncating, 9 were missense, of which one was recurrent. The disorder is characterized by intellectual disability with variable cardiovascular, ophthalmologic and minor skeletal anomalies. Missense variants in the PWWP domain of ZMYND8 abolish the interaction with Drebrin and missense variants in the MYND domain disrupt the interaction with GATAD2A. ZMYND8 is broadly expressed across cell types in all brain regions and shows highest expression in the early stages of brain development. Neuronal knockdown of the DrosophilaZMYND8 ortholog results in decreased habituation learning, consistent with a role in cognitive function.
CONCLUSION: We present genomic and functional evidence for disruption of ZMYND8 as a novel etiology of syndromic intellectual disability.
August 1, 2022
Genetic Neurologic Disease
Efficacy of Caffeine in ADCY5-Related Dyskinesia: A Retrospective Study
Méneret A, Mohammad SS, Cif L, Doummar D, DeGusmao C, Anheim M, Barth M, Damier P, Demonceau N, Friedman J, Gallea C, Gras D, Gurgel-Giannetti J, Innes EA, Necpál J, Riant F, Sagnes S, Sarret C, Seliverstov Y, Paramanandam V, Shetty K, Tranchant C, Doulazmi M, Vidailhet M, Pringsheim T, Roze E.
Mov Disord. 2022 Apr 5. doi: 10.1002/mds.29006. Online ahead of print.
BACKGROUND: ADCY5-related dyskinesia is characterized by early-onset movement disorders. There is currently no validated treatment, but anecdotal clinical reports and biological hypotheses suggest efficacy of caffeine.
OBJECTIVE: The aim is to obtain further insight into the efficacy and safety of caffeine in patients with ADCY5-related dyskinesia.
METHODS: A retrospective study was conducted worldwide in 30 patients with a proven ADCY5 mutation who had tried or were taking caffeine for dyskinesia. Disease characteristics and treatment responses were assessed through a questionnaire.
RESULTS: Caffeine was overall well tolerated, even in children, and 87% of patients reported a clear improvement. Caffeine reduced the frequency and duration of paroxysmal movement disorders but also improved baseline movement disorders and some other motor and nonmotor features, with consistent quality-of-life improvement. Three patients reported worsening.
CONCLUSION: Our findings suggest that caffeine should be considered as a first-line therapeutic option in ADCY5-related dyskinesia. © 2022 International Parkinson and Movement Disorder Society.
April 5, 2022
Genetic Neurologic Disease
Consolidation of the clinical and genetic definition of a SOX4-related neurodevelopmental syndrome
Angelozzi M, Karvande A, Molin AN, Ritter AL, Leonard JMM, Savatt JM, Douglass K, Myers SM, Grippa M, Tolchin D, Zackai E, Donoghue S, Hurst ACE, Descartes M, Smith K, Velasco D, Schmanski A, Crunk A, Tokita MJ, de Lange IM, van Gassen K, Robinson H, Guegan K, Suri M, Patel C, Bournez M, Faivre L, Tran-Mau-Them F, Baker J, Fabie N, Weaver K, Shillington A, Hopkin RJ, Barge-Schaapveld DQCM, Ruivenkamp CA, Bökenkamp R, Vergano S, Seco Moro MN, Díaz de Bustamante A, Misra VK, Kennelly K, Rogers C, Friedman J, Wigby KM, Lenberg J, Graziano C, Ahrens-Nicklas RC, Lefebvre V.
J Med Genet. 2022 Mar 1:jmedgenet-2021-108375. doi: 10.1136/jmedgenet-2021-108375. Epub ahead of print. PMID: 35232796.
Background: A neurodevelopmental syndrome was recently reported in four patients with SOX4 heterozygous missense variants in the high-mobility-group (HMG) DNA-binding domain. The present study aimed to consolidate clinical and genetic knowledge of this syndrome.
Methods: We newly identified 17 patients with SOX4 variants, predicted variant pathogenicity using in silico tests and in vitro functional assays and analysed the patients’ phenotypes.
Results: All variants were novel, distinct and heterozygous. Seven HMG-domain missense and five stop-gain variants were classified as pathogenic or likely pathogenic variant (L/PV) as they precluded SOX4 transcriptional activity in vitro. Five HMG-domain and non-HMG-domain missense variants were classified as of uncertain significance (VUS) due to negative results from functional tests. When known, inheritance was de novo or from a mosaic unaffected or non-mosaic affected parent for patients with L/PV, and from a non-mosaic asymptomatic or affected parent for patients with VUS. All patients had neurodevelopmental, neurological and dysmorphic features, and at least one cardiovascular, ophthalmological, musculoskeletal or other somatic anomaly. Patients with L/PV were overall more affected than patients with VUS. They resembled patients with other neurodevelopmental diseases, including the SOX11-related and Coffin-Siris (CSS) syndromes, but lacked the most specific features of CSS.
Conclusion: These findings consolidate evidence of a fairly non-specific neurodevelopmental syndrome due to SOX4 haploinsufficiency in neurogenesis and multiple other developmental processes.
PMID: 35232796 | DOI: 10.1136/jmedgenet-2021-108375
March 1, 2022
Genetic Neurologic DiseaseNeurogenomics
Autosomal Recessive Cerebellar Atrophy and Spastic Ataxia in Patients With Pathogenic Biallelic Variants in GEMIN5
Rajan DS, Kour S, Fortuna TR, Cousin MA, Barnett SS, Niu Z, Babovic-Vuksanovic D, Klee EW, Kirmse B, Innes M, Rydning SL, Selmer KK, Vigeland MD, Erichsen AK, Nemeth AH, Millan F, DeVile C, Fawcett K, Legendre A, Sims D, Schnekenberg RP, Burglen L, Mercier S, Bakhtiari S, Martinez-Salas E, Wigby K, Lenberg J, Friedman JR, Kruer MC, Pandey UB.
Front Cell Dev Biol. 2022 Feb 28;10:783762. doi: 10.3389/fcell.2022.783762. eCollection 2022.
The hereditary ataxias are a heterogenous group of disorders with an increasing number of causative genes being described. Due to the clinical and genetic heterogeneity seen in these conditions, the majority of such individuals endure a diagnostic odyssey or remain undiagnosed. Defining the molecular etiology can bring insights into the responsible molecular pathways and eventually the identification of therapeutic targets. Here, we describe the identification of biallelic variants in the GEMIN5 gene among seven unrelated families with nine affected individuals presenting with spastic ataxia and cerebellar atrophy. GEMIN5, an RNA-binding protein, has been shown to regulate transcription and translation machinery. GEMIN5 is a component of small nuclear ribonucleoprotein (snRNP) complexes and helps in the assembly of the spliceosome complexes. We found that biallelic GEMIN5 variants cause structural abnormalities in the encoded protein and reduce expression of snRNP complex proteins in patient cells compared with unaffected controls. Finally, knocking out endogenous Gemin5 in mice caused early embryonic lethality, suggesting that Gemin5 expression is crucial for normal development. Our work further expands on the phenotypic spectrum associated with GEMIN5-related disease and implicates the role of GEMIN5 among patients with spastic ataxia, cerebellar atrophy, and motor predominant developmental delay.
February 28, 2022
Genetic Neurologic Disease
Ending a diagnostic odyssey: Moving from exome to genome to identify cockayne syndrome
Friedman J, Bird LM, Haas R, Robbins SL, Nahas SA, Dimmock DP, Yousefzadeh MJ, Witt MA, Niedernhofer LJ, Chowdhury S.
Mol Genet Genomic Med. 2021 Jun 2:e1623. doi: 10.1002/mgg3.1623. Online ahead of print.
BACKGROUND: Cockayne syndrome (CS) is a rare autosomal recessive disorder characterized by growth failure and multisystemic degeneration. Excision repair cross-complementation group 6 (ERCC6 OMIM: *609413) is the gene most frequently mutated in CS.
METHODS: A child with pre and postnatal growth failure and progressive neurologic deterioration with multisystem involvement, and with nondiagnostic whole-exome sequencing, was screened for causal variants with whole-genome sequencing (WGS).
RESULTS: WGS identified biallelic ERCC6 variants, including a previously unreported intronic variant. Pathogenicity of these variants was established by demonstrating reduced levels of ERCC6 mRNA and protein expression, normal unscheduled DNA synthesis, and impaired recovery of RNA synthesis in patient fibroblasts following UV-irradiation.
CONCLUSION: The study confirms the pathogenicity of a previously undescribed upstream intronic variant, highlighting the power of genome sequencing to identify noncoding variants. In addition, this report provides evidence for the utility of a combination approach of genome sequencing plus functional studies to provide diagnosis in a child for whom a lengthy diagnostic odyssey, including exome sequencing, was previously unrevealing.
June 2, 2021
Genetic Neurologic DiseaseRare Disease
Rare deleterious mutations of HNRNP genes result in shared neurodevelopmental disorders
Gillentine MA, Wang T, Hoekzema K, Rosenfeld J, Liu P, Guo H, Kim CN, De Vries BBA, Vissers LELM, Nordenskjold M, Kvarnung M, Lindstrand A, Nordgren A, Gecz J, Iascone M, Cereda A, Scatigno A, Maitz S, Zanni G, Bertini E, Zweier C, Schuhmann S, Wiesener A, Pepper M, Panjwani H, Torti E, Abid F, Anselm I, Srivastava S, Atwal P, Bacino CA, Bhat G, Cobian K, Bird LM, Friedman J, Wright MS, Callewaert B, Petit F, Mathieu S, Afenjar A, Christensen CK, White KM, Elpeleg O, Berger I, Espineli EJ, Fagerberg C, Brasch-Andersen C, Hansen LK, Feyma T, Hughes S, Thiffault I, Sullivan B, Yan S, Keller K, Keren B, Mignot C, Kooy F, Meuwissen M, Basinger A, Kukolich M, Philips M, Ortega L, Drummond-Borg M, Lauridsen M, Sorensen K, Lehman A; CAUSES Study, Lopez-Rangel E, Levy P, Lessel D, Lotze T, Madan-Khetarpal S, Sebastian J, Vento J, Vats D, Benman LM, Mckee S, Mirzaa GM, Muss C, Pappas J, Peeters H, Romano C, Elia M, Galesi O, Simon MEH, van Gassen KLI, Simpson K, Stratton R, Syed S, Thevenon J, Palafoll IV, Vitobello A, Bournez M, Faivre L, Xia K; SPARK Consortium, Earl RK, Nowakowski T, Bernier RA, Eichler EE.
Madelyn A Gillentine
Genome Med. 2021 Apr 19;13(1):63. doi: 10.1186/s13073-021-00870-6.
BACKGROUND: With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype-phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations.
METHODS: We tested our hypothesis by considering gene families that have multiple members with an enrichment of de novo variants among NDDs, as determined by previous meta-analyses. One of these gene families is the heterogeneous nuclear ribonucleoproteins (hnRNPs), which has 33 members, five of which have been recently identified as NDD genes (HNRNPK, HNRNPU, HNRNPH1, HNRNPH2, and HNRNPR) and two of which have significant enrichment in our previous meta-analysis of probands with NDDs (HNRNPU and SYNCRIP). Utilizing protein homology, mutation analyses, gene expression analyses, and phenotypic characterization, we provide evidence for variation in 12 HNRNP genes as candidates for NDDs. Seven are potentially novel while the remaining genes in the family likely do not significantly contribute to NDD risk.
RESULTS: We report 119 new NDD cases (64 de novo variants) through sequencing and international collaborations and combined with published clinical case reports. We consider 235 cases with gene-disruptive single-nucleotide variants or indels and 15 cases with small copy number variants. Three hnRNP-encoding genes reach nominal or exome-wide significance for de novo variant enrichment, while nine are candidates for pathogenic mutations. Comparison of HNRNP gene expression shows a pattern consistent with a role in cerebral cortical development with enriched expression among radial glial progenitors. Clinical assessment of probands (n = 188-221) expands the phenotypes associated with HNRNP rare variants, and phenotypes associated with variation in the HNRNP genes distinguishes them as a subgroup of NDDs.
CONCLUSIONS: Overall, our novel approach of exploiting gene families in NDDs identifies new HNRNP-related disorders, expands the phenotypes of known HNRNP-related disorders, strongly implicates disruption of the hnRNPs as a whole in NDDs, and supports that NDD subtypes likely have shared molecular pathogenesis. To date, this is the first study to identify novel genetic disorders based on the presence of disorders in related genes. We also perform the first phenotypic analyses focusing on related genes. Finally, we show that radial glial expression of these genes is likely critical during neurodevelopment. This is important for diagnostics, as well as developing strategies to best study these genes for the development of therapeutics.
April 20, 2021
Gene DiscoveryGenetic Neurologic DiseaseNeurogenomics
Brain MR patterns in inherited disorders of monoamine neurotransmitters: An analysis of 70 patients
Kuseyri Hübschmann O, Mohr A, Friedman J, Manti F, Horvath G, Cortès-Saladelafont E, Mercimek-Andrews S, Yildiz Y, Pons R, Kulhánek J, Oppebøen M, Koht JA, Podzamczer-Valls I, Domingo-Jimenez R, Ibáñez S, Alcoverro-Fortuny O, Gómez-Alemany T, de Castro P, Alfonsi C, Zafeiriou DI, López-Laso E, Guder P, Santer R, Honzík T, Hoffmann GF, Garbade SF, Sivri HS, Leuzzi V, Jeltsch K, García-Cazorla A, Opladen T; International Working Group on Neurotransmitter Related Disorders (iNTD), Harting I.
J Inherit Metab Dis. 2021 Jan 14. doi: 10.1002/jimd.12360. Online ahead of print.
Inherited monoamine neurotransmitter disorders (iMNDs) are rare disorders with clinical manifestations ranging from mild infantile hypotonia, movement disorders to early infantile severe encephalopathy. Neuroimaging has been reported as non-specific. We systematically analyzed brain MRIs in order to characterize and better understand neuroimaging changes and to re-evaluate the diagnostic role of brain MRI in iMNDs. 81 MRIs of 70 patients (0.1-52.9 years, 39 patients with tetrahydrobiopterin deficiencies, 31 with primary disorders of monoamine metabolism) were retrospectively analyzed and clinical records reviewed. 33/70 patients had MRI changes, most commonly atrophy (n = 24). Eight patients, six with dihydropteridine reductase deficiency (DHPR), had a common pattern of bilateral parieto-occipital and to a lesser extent frontal and/or cerebellar changes in arterial watershed zones. Two patients imaged after acute severe encephalopathy had signs of profound hypoxic-ischemic injury and a combination of deep gray matter and watershed injury (aromatic l-amino acid decarboxylase (AADCD), tyrosine hydroxylase deficiency (THD)). Four patients had myelination delay (AADCD; THD); two had changes characteristic of post-infantile onset neuronal disease (AADCD, monoamine oxidase A deficiency), and nine T2-hyperintensity of central tegmental tracts. iMNDs are associated with MRI patterns consistent with chronic effects of a neuronal disorder and signs of repetitive injury to cerebral and cerebellar watershed areas, in particular in DHPRD. These will be helpful in the (neuroradiological) differential diagnosis of children with unknown disorders and monitoring of iMNDs. We hypothesize that deficiency of catecholamines and/or tetrahydrobiopterin increase the incidence of and the CNS susceptibility to vascular dysfunction.
January 14, 2021
Genetic Neurologic Disease