Neurology-GeneticsPub Date : 2023-10-25DOI: 10.1212/nxg.0000000000200104
Carlo Manco, Rosa Cortese, Manfredi Alberti, Silvia Bianchi, Lucia Monti, Nicola De Stefano, Carla Battisti
{"title":"<i>FOLR1</i>Gene Variation With Adult-Onset Cerebral Folate Deficiency and Stable Clinical and MRI Features up to 2 Years","authors":"Carlo Manco, Rosa Cortese, Manfredi Alberti, Silvia Bianchi, Lucia Monti, Nicola De Stefano, Carla Battisti","doi":"10.1212/nxg.0000000000200104","DOIUrl":"https://doi.org/10.1212/nxg.0000000000200104","url":null,"abstract":"Objectives The objective of this case report was to describe the first report of FOLR1 variants associated with adult-onset paucisymptomatic leukoencephalopathy associated with cerebral folate deficiency (CFD). Methods Considering the patient's symptoms, a nonprogressive leukoencephalopathy was suspected. CSF 5-methyltetrahydrofolate levels were low (10 nmol/L, normal range 41–117). With no other identifiable causes, a genetic analysis was conducted, revealing a compound heterozygous FOLR1 variation (c.45G>T and c. 493+2T>C). Results A 47-year-old man with a history of drug and alcohol abuse was admitted to the hospital for double vision and postural instability. MRI of the brain was performed, which showed bilateral leukoencephalopathy. Diffusion tensor imaging revealed a diffuse reduction in fractional anisotropy, suggesting microstructural changes. MRI of the brain and overall clinical picture were stable on subsequent serial examinations. Discussion Scientific evidence supports the deleterious effect of c.45G>T and c.493+2T>C variations on the folate receptor-α (FRα) protein structure and function. The weakness of the expression and function of FRα without elimination of its function caused by specific compound heterozygous variations may explain the atypical features observed in our patient. Although rare, CFD should be considered in paucisymptomatic adult patients with stable diffuse MRI white matter changes.","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135217076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-10-19DOI: 10.1212/nxg.0000000000200096
Solveig Heide, Claire-Sophie Davoine, Paulina Cunha, Clarisse Scherer-Gagou, Boris Keren, Giovanni Stevanin, Perrine Charles, Delphine Heron, Alexis Brice, Alexandra Durr
{"title":"<i>IRF2BPL</i>Causes Mild Intellectual Disability Followed by Late-Onset Ataxia","authors":"Solveig Heide, Claire-Sophie Davoine, Paulina Cunha, Clarisse Scherer-Gagou, Boris Keren, Giovanni Stevanin, Perrine Charles, Delphine Heron, Alexis Brice, Alexandra Durr","doi":"10.1212/nxg.0000000000200096","DOIUrl":"https://doi.org/10.1212/nxg.0000000000200096","url":null,"abstract":"Background and Objectives Neurodevelopmental and neurodegenerative disorders have long been considered as different clinical and molecular entities, and only a few genes are known to be involved in both processes. The IRF2BPL (interferon regulatory factor 2 binding protein like) gene was implicated in a severe pediatric phenotype characterized by developmental and epileptic encephalopathy and early regression. In parallel, inherited IRF2BPL variants have been reported in cohorts of patients with late-onset progressive dystonic and ataxic syndrome with few information about the neurodevelopment of these patients. This study aimed to describe both neurodevelopmental and neurodegenerative aspects of the phenotype in adults with IRF2BPL pathogenic variant. Methods We report here the clinical and molecular data of 18 individuals carrying truncating IRF2BPL variants (identified by either exome or genome sequencing), including a large pedigree of 16 patients presenting with a neurodevelopmental disorder (NDD) associated with late-onset cerebellar ataxia and atrophy. Results Genome sequencing identified the p.(Gln117*) variant in a large family first assessed for familial ataxia, with multiple individuals presenting with NDD. The p.(Ser313*) variant was identified by exome sequencing in a second family with a young adult patient with NDD without ataxia which was inherited from her asymptomatic mother, suggesting incomplete penetrance of IRF2BPL -linked disorders. Discussion This study illustrates the importance of neurologic evaluation of adult patients initially diagnosed with NDD to detect a late-onset neurodegenerative condition. Two different disorders may be clinically diagnosed in the same family, when not considering that NDD and late cerebellar changes may be part of the same molecular spectrum such as for IRF2BPL .","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135729231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-09-26DOI: 10.1212/nxg.0000000000200101
Kristen N. Wong, Lorenzo D. Botto, Miao He, Peter R. Baker, Adeline L. Vanderver, Joshua L. Bonkowsky
{"title":"Novel<i>SLC13A3</i>Variants and Cases of Acute Reversible Leukoencephalopathy and α-Ketoglutarate Accumulation and Literature Review","authors":"Kristen N. Wong, Lorenzo D. Botto, Miao He, Peter R. Baker, Adeline L. Vanderver, Joshua L. Bonkowsky","doi":"10.1212/nxg.0000000000200101","DOIUrl":"https://doi.org/10.1212/nxg.0000000000200101","url":null,"abstract":"Objectives Acute reversible leukoencephalopathy with increased urinary alpha-ketoglutarate (ARLIAK) is a recently described autosomal recessive leukoencephalopathy caused by pathogenic variants in the SLC13A3 gene. ARLIAK is characterized by acute neurologic involvement, often precipitated by febrile illness, with largely reversible clinical symptoms and imaging findings. Three patients have been reported in the literature to date. Our objective is to report newly identified patients and their genetic variants and phenotypes and review published literature on ARLIAK. Methods This report contributes 4 additional patients to the literature; describes novel variants in SLC13A3 ; and reviews genetic, biochemical, clinical, and radiologic features of all published patients with ARLIAK. Results We provide additional genetic, imaging, and laboratory insights into ARLIAK, an atypical leukodystrophy with clinical and radiologic findings that can normalize. Discussion Our case series highlights the importance of reanalysis of next-generation sequencing in the diagnostic workup.","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134885229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-09-26DOI: 10.1212/nxg.0000000000200102
Erika K. Williams, Cristina Shea, Paloma Gonzalez-Perez
{"title":"Agenesis of Pectoralis Major Muscle in Late-Onset<i>GFPT1</i>-Related Congenital Myasthenic Syndrome","authors":"Erika K. Williams, Cristina Shea, Paloma Gonzalez-Perez","doi":"10.1212/nxg.0000000000200102","DOIUrl":"https://doi.org/10.1212/nxg.0000000000200102","url":null,"abstract":"Objectives The objective of this study was to expand the phenotypic spectrum of glutamine-fructose-6-phosphate transaminase 1 ( GFPT1 )–related congenital myasthenia syndrome (CMS). Methods A 61-year-old man with agenesis of the left pectoralis major muscle presented with progressive muscle weakness for a decade that transiently improved after exertion. Results His examination revealed proximal and distal muscle weakness in upper extremities and proximal muscle weakness in lower extremities. Muscle enzymes were elevated. An electromyogram revealed a myopathic pattern; however, a muscle biopsy of deltoid muscle and genetic testing for limb-girdle muscular dystrophies were nondiagnostic. A 3-Hz repetitive nerve stimulation of the spinal accessory nerve recording from trapezius muscle demonstrated a >20% drop in amplitude of the 5th compound motor action potential relative to 1st at both baseline and after 45-second exercise. Acetylcholine receptor binding, lipoprotein-related protein 4, muscle-specific kinase, and voltage-gated calcium channel P/Q antibodies were negative. Genetic testing targeting CMS revealed 2 likely pathogenic variants within GFPT1 : novel c.7+2T>G (intron 1) that was predicted to result in a null allele and known c*22 C>A (exon 19) associated with reduced GFPT1 expression. His muscle strength dramatically improved after pyridostigmine initiation. Discussion In addition to other reported neurodevelopmental abnormalities, pectoralis major muscle agenesis (or Poland syndrome) may be a clinical manifestation of GFPT1 -related CMS.","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134885221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-09-19DOI: 10.1212/nxg.0000000000200088
Jodi Warman-Chardon, Taila Hartley, Aren Elizabeth Marshall, Arran McBride, Madeline Couse, William Macdonald, Mellissa R.W. Mann, Pierre R. Bourque, Ari Breiner, Hanns Lochmüller, John Woulfe, Marcos Loreto Sampaio, Gerd Melkus, Bernard Brais, David A. Dyment, Kym M. Boycott, Kristin Kernohan
{"title":"Biallelic<i>SOX8</i>Variants Associated With Novel Syndrome With Myopathy, Skeletal Deformities, Intellectual Disability, and Ovarian Dysfunction","authors":"Jodi Warman-Chardon, Taila Hartley, Aren Elizabeth Marshall, Arran McBride, Madeline Couse, William Macdonald, Mellissa R.W. Mann, Pierre R. Bourque, Ari Breiner, Hanns Lochmüller, John Woulfe, Marcos Loreto Sampaio, Gerd Melkus, Bernard Brais, David A. Dyment, Kym M. Boycott, Kristin Kernohan","doi":"10.1212/nxg.0000000000200088","DOIUrl":"https://doi.org/10.1212/nxg.0000000000200088","url":null,"abstract":"Background and Objectives The human genome contains ∼20,000 genes, each of which has its own set of complex regulatory systems to govern precise expression in each developmental stage and cell type. Here, we report a female patient with congenital weakness, respiratory failure, skeletal dysplasia, contractures, short stature, intellectual delay, respiratory failure, and amenorrhea who presented to Medical Genetics service with no known cause for her condition. Methods Whole-exome and whole-genome sequencing were conducted, as well as investigational functional studies to assess the effect of SOX8 variant. Results The patient was found to have biallelic SOX8 variants (NM_014587.3:c.422+5G>C; c.583dup p.(His195ProfsTer11)). SOX8 is a transcriptional regulator, which is predicted to be imprinted (expressed from only one parental allele), but this has not yet been confirmed. We provide evidence that while SOX8 was maternally expressed in adult-derived fibroblasts and lymphoblasts, it was biallelically expressed in other cell types and therefore suggest that biallelic variants are associated with this recessive condition. Functionally, we showed that the paternal variant had the capacity to affect mRNA splicing while the maternal variant resulted in low levels of a truncated protein, which showed decreased binding at and altered expression of SOX8 targets. Discussion Our findings associate SOX8 variants with this novel condition, highlight how complex genome regulation can complicate novel disease-gene identification, and provide insight into the molecular pathogenesis of this disease.","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135059469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-08-28eCollection Date: 2023-10-01DOI: 10.1212/NXG.0000000000200094
Luiz Eduardo Novis, Rodrigo S Frezatti, David Pellerin, Pedro J Tomaselli, Shahryar Alavi, Marcus Vinícius Della Coleta, Mariana Spitz, Marie-Josée Dicaire, Pablo Iruzubieta, José Luiz Pedroso, Orlando Barsottini, Andrea Cortese, Matt C Danzi, Marcondes C França, Bernard Brais, Stephan Zuchner, Henry Houlden, Salmo Raskin, Wilson Marques, Helio A Teive
{"title":"Frequency of GAA-<i>FGF14</i> Ataxia in a Large Cohort of Brazilian Patients With Unsolved Adult-Onset Cerebellar Ataxia.","authors":"Luiz Eduardo Novis, Rodrigo S Frezatti, David Pellerin, Pedro J Tomaselli, Shahryar Alavi, Marcus Vinícius Della Coleta, Mariana Spitz, Marie-Josée Dicaire, Pablo Iruzubieta, José Luiz Pedroso, Orlando Barsottini, Andrea Cortese, Matt C Danzi, Marcondes C França, Bernard Brais, Stephan Zuchner, Henry Houlden, Salmo Raskin, Wilson Marques, Helio A Teive","doi":"10.1212/NXG.0000000000200094","DOIUrl":"10.1212/NXG.0000000000200094","url":null,"abstract":"<p><strong>Objectives: </strong>Intronic <i>FGF14</i> GAA repeat expansions have recently been found to be a common cause of hereditary ataxia (GAA-<i>FGF14</i> ataxia; SCA27B). The global epidemiology and regional prevalence of this newly reported disorder remain to be established. In this study, we investigated the frequency of GAA-<i>FGF14</i> ataxia in a large cohort of Brazilian patients with unsolved adult-onset ataxia.</p><p><strong>Methods: </strong>We recruited 93 index patients with genetically unsolved adult-onset ataxia despite extensive genetic investigation and genotyped the <i>FGF14</i> repeat locus. Patients were recruited across 4 different regions of Brazil.</p><p><strong>Results: </strong>Of the 93 index patients, 8 (9%) carried an <i>FGF14</i> (GAA)<sub>≥250</sub> expansion. The expansion was also identified in 1 affected relative. Seven patients were of European descent, 1 was of African descent, and 1was of admixed American ancestry. One patient carrying a (GAA)<sub>376</sub> expansion developed ataxia at age 28 years, confirming that GAA-<i>FGF14</i> ataxia can occur before the age of 30 years. One patient displayed episodic symptoms, while none had downbeat nystagmus. Cerebellar atrophy was observed on brain MRI in 7 of 8 patients (87%).</p><p><strong>Discussion: </strong>Our results suggest that GAA-<i>FGF14</i> ataxia is a common cause of adult-onset ataxia in the Brazilian population, although larger studies are needed to fully define its epidemiology.</p>","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"9 5","pages":"e200094"},"PeriodicalIF":3.0,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10461713/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10118312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-08-15eCollection Date: 2023-10-01DOI: 10.1212/NXG.0000000000200093
Marianela Schiava, Chiseko Ikenaga, Ana Topf, Marta Caballero-Ávila, Tsui-Fen Chou, Shan Li, Feng Wang, Jil Daw, Tanya Stojkovic, Rocio Villar-Quiles, Ichizo Nishino, Michio Inoue, Yukako Nishimori, Yoshihiko Saito, Masahisa Katsuno, Seiya Noda, Chihiro Ito, Mieko Otsuka, Sruthi Nahir, Georgios Manousakis, David Walk, Colin Quinn, Lindsay Alfano, Zarife Sahenk, Giorgio Tasca, Mauro Monforte, Mario Sabatelli, Giulia Bisogni, Anders Oldfors, Anna Rydeliu, Endre Pal, Carmen Paradas, Beatriz Velez, Jan L De Bleecker, Maria Elena Farugia, Cheryl Longman, Matthew B Harms, Stuart Ralston, Edmar Zanoteli, Andre Macedo Serafim da Silva, Javier Sotoca, Raul Juntas-Morales, Jorge Bevilacqua, Mireya Balart, Stuart Talbot, Volker Straub, Michela Guglieri, Chiara Marini-Bettolo, Jordi Diaz-Manera, Conrad Chris Weihl
{"title":"Clinical Classification of Variants in the Valosin-Containing Protein Gene Associated With Multisystem Proteinopathy.","authors":"Marianela Schiava, Chiseko Ikenaga, Ana Topf, Marta Caballero-Ávila, Tsui-Fen Chou, Shan Li, Feng Wang, Jil Daw, Tanya Stojkovic, Rocio Villar-Quiles, Ichizo Nishino, Michio Inoue, Yukako Nishimori, Yoshihiko Saito, Masahisa Katsuno, Seiya Noda, Chihiro Ito, Mieko Otsuka, Sruthi Nahir, Georgios Manousakis, David Walk, Colin Quinn, Lindsay Alfano, Zarife Sahenk, Giorgio Tasca, Mauro Monforte, Mario Sabatelli, Giulia Bisogni, Anders Oldfors, Anna Rydeliu, Endre Pal, Carmen Paradas, Beatriz Velez, Jan L De Bleecker, Maria Elena Farugia, Cheryl Longman, Matthew B Harms, Stuart Ralston, Edmar Zanoteli, Andre Macedo Serafim da Silva, Javier Sotoca, Raul Juntas-Morales, Jorge Bevilacqua, Mireya Balart, Stuart Talbot, Volker Straub, Michela Guglieri, Chiara Marini-Bettolo, Jordi Diaz-Manera, Conrad Chris Weihl","doi":"10.1212/NXG.0000000000200093","DOIUrl":"10.1212/NXG.0000000000200093","url":null,"abstract":"<p><strong>Background and objectives: </strong>Pathogenic variants in the valosin-containing protein (<i>VCP</i>) gene cause a phenotypically heterogeneous disorder that includes myopathy, motor neuron disease, Paget disease of the bone, frontotemporal dementia, and parkinsonism termed multisystem proteinopathy. This hallmark pleiotropy makes the classification of novel <i>VCP</i> variants challenging. This retrospective study describes and assesses the effect of 19 novel or nonpreviously clinically characterized <i>VCP</i> variants identified in 28 patients (26 unrelated families) in the retrospective VCP International Multicenter Study.</p><p><strong>Methods: </strong>A 6-item clinical score was developed to evaluate the phenotypic level of evidence to support the pathogenicity of the novel variants. Each item is allocated a value, a score ranging from 0.5 to 5.5 points. A receiver-operating characteristic curve was used to identify a cutoff value of 3 to consider a variant as high likelihood disease associated. The scoring system results were confronted with results of in vitro ATPase activity assays and with in silico analysis.</p><p><strong>Results: </strong>All variants were missense, except for one small deletion-insertion, 18 led to amino acid changes within the N and D1 domains, and 13 increased the enzymatic activity. The clinical score coincided with the functional studies in 17 of 19 variants and with the in silico analysis in 12 of 19. For 12 variants, the 3 predictive tools agreed, and for 7 variants, the predictive tools disagreed. The pooled data supported the pathogenicity of 13 of 19 novel VCP variants identified in the study.</p><p><strong>Discussion: </strong>This study provides data to support pathogenicity of 14 of 19 novel <i>VCP</i> variants and provides guidance for clinicians in the evaluation of novel variants in the <i>VCP</i> gene.</p>","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"9 5","pages":"e200093"},"PeriodicalIF":3.0,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/d1/07/NXG-2023-000033.PMC10427110.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10020392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-08-08eCollection Date: 2023-10-01DOI: 10.1212/NXG.0000000000200090
Andrew B Stergachis, Elizabeth E Blue, Madelyn A Gillentine, Lee-Kai Wang, Ulrike Schwarze, Adriana Sedeño Cortés, Jane Ranchalis, Aimee Allworth, Austin E Bland, Sirisak Chanprasert, Jingheng Chen, Daniel Doherty, Andrew B Folta, Ian Glass, Martha Horike-Pyne, Alden Y Huang, Alyna T Khan, Kathleen A Leppig, Danny E Miller, Ghayda Mirzaa, Azma Parhin, Wendy H Raskind, Elisabeth A Rosenthal, Sam Sheppeard, Samuel Strohbehn, Virginia P Sybert, Thao T Tran, Mark H Wener, Peter H H Byers, Stanley F Nelson, Michael J Bamshad, Katrina M Dipple, Gail P Jarvik, Suzanne Hoppins, Fuki M Hisama
{"title":"Full-length Isoform Sequencing for Resolving the Molecular Basis of Charcot-Marie-Tooth 2A.","authors":"Andrew B Stergachis, Elizabeth E Blue, Madelyn A Gillentine, Lee-Kai Wang, Ulrike Schwarze, Adriana Sedeño Cortés, Jane Ranchalis, Aimee Allworth, Austin E Bland, Sirisak Chanprasert, Jingheng Chen, Daniel Doherty, Andrew B Folta, Ian Glass, Martha Horike-Pyne, Alden Y Huang, Alyna T Khan, Kathleen A Leppig, Danny E Miller, Ghayda Mirzaa, Azma Parhin, Wendy H Raskind, Elisabeth A Rosenthal, Sam Sheppeard, Samuel Strohbehn, Virginia P Sybert, Thao T Tran, Mark H Wener, Peter H H Byers, Stanley F Nelson, Michael J Bamshad, Katrina M Dipple, Gail P Jarvik, Suzanne Hoppins, Fuki M Hisama","doi":"10.1212/NXG.0000000000200090","DOIUrl":"10.1212/NXG.0000000000200090","url":null,"abstract":"<p><strong>Objectives: </strong>Transcript sequencing of patient-derived samples has been shown to improve the diagnostic yield for solving cases of suspected Mendelian conditions, yet the added benefit of full-length long-read transcript sequencing is largely unexplored.</p><p><strong>Methods: </strong>We applied short-read and full-length transcript sequencing and mitochondrial functional studies to a patient-derived fibroblast cell line from an individual with neuropathy that previously lacked a molecular diagnosis.</p><p><strong>Results: </strong>We identified an intronic homozygous <i>MFN2</i> c.600-31T>G variant that disrupts the branch point critical for intron 6 splicing. Full-length long-read isoform complementary DNA (cDNA) sequencing after treatment with a nonsense-mediated mRNA decay (NMD) inhibitor revealed that this variant creates 5 distinct altered splicing transcripts. All 5 altered splicing transcripts have disrupted open reading frames and are subject to NMD. Furthermore, a patient-derived fibroblast line demonstrated abnormal lipid droplet formation, consistent with MFN2 dysfunction. Although correctly spliced full-length <i>MFN2</i> transcripts are still produced, this branch point variant results in deficient MFN2 levels and autosomal recessive Charcot-Marie-Tooth disease, axonal, type 2A (CMT2A).</p><p><strong>Discussion: </strong>This case highlights the utility of full-length isoform sequencing for characterizing the molecular mechanism of undiagnosed rare diseases and expands our understanding of the genetic basis for CMT2A.</p>","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"9 5","pages":"e200090"},"PeriodicalIF":3.1,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/f3/32/NXG-2023-000030.PMC10409571.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10002928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-08-08eCollection Date: 2023-10-01DOI: 10.1212/NXG.0000000000200092
Alejandro Martínez Carrasco, Raquel Real, Michael Lawton, Regina Hertfelder Reynolds, Manuela Tan, Lesley Wu, Nigel Williams, Camille Carroll, Jean-Christophe Corvol, Michele Hu, Donald Grosset, John Hardy, Mina Ryten, Yoav Ben-Shlomo, Maryam Shoai, Huw R Morris
{"title":"Genome-wide Analysis of Motor Progression in Parkinson Disease.","authors":"Alejandro Martínez Carrasco, Raquel Real, Michael Lawton, Regina Hertfelder Reynolds, Manuela Tan, Lesley Wu, Nigel Williams, Camille Carroll, Jean-Christophe Corvol, Michele Hu, Donald Grosset, John Hardy, Mina Ryten, Yoav Ben-Shlomo, Maryam Shoai, Huw R Morris","doi":"10.1212/NXG.0000000000200092","DOIUrl":"10.1212/NXG.0000000000200092","url":null,"abstract":"<p><strong>Background and objectives: </strong>The genetic basis of Parkinson disease (PD) motor progression is largely unknown. Previous studies of the genetics of PD progression have included small cohorts and shown a limited overlap with genetic PD risk factors from case-control studies. Here, we have studied genomic variation associated with PD motor severity and early-stage progression in large longitudinal cohorts to help to define the biology of PD progression and potential new drug targets.</p><p><strong>Methods: </strong>We performed a GWAS meta-analysis of early PD motor severity and progression up to 3 years from study entry. We used linear mixed-effect models with additive effects, corrected for age at diagnosis, sex, and the first 5 genetic principal components to assess variability in axial, limb, and total Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) III scores.</p><p><strong>Results: </strong>We included 3,572 unrelated European ancestry patients with PD from 5 observational cohorts and 1 drug trial. The average AAO was 62.6 years (SD = 9.83), and 63% of participants were male. We found an average increase in the total MDS-UPDRS III score of 2.3 points/year. We identified an association between PD axial motor progression and variation at the <i>GJA5</i> locus at 1q12 (β = -0.25, SE = 0.04, <i>p</i> = 3.4e<sup>-10</sup>). Exploration of the regulation of gene expression in the region (<i>cis</i>-expression quantitative trait loci [eQTL] analysis) showed that the lead variant was associated with expression of <i>ACP6</i>, a lysophosphatidic acid phosphatase that regulates mitochondrial lipid biosynthesis (cis-eQTL <i>p</i>-values in blood and brain RNA expression data sets: <10<sup>-14</sup> in eQTLGen and 10<sup>-7</sup> in PsychEncode).</p><p><strong>Discussion: </strong>Our study highlights the potential role of mitochondrial lipid homeostasis in the progression of PD, which may be important in establishing new drug targets that might modify disease progression.</p>","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"9 5","pages":"e200092"},"PeriodicalIF":3.1,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/86/92/NXG-2023-000032.PMC10409573.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10026949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neurology-GeneticsPub Date : 2023-08-02eCollection Date: 2023-10-01DOI: 10.1212/NXG.0000000000200083
Changrui Xiao, Thomas Cassini, Daniel Benavides, Anusha Ebrahim, David Adams, Camilo Toro
{"title":"Genomic Diagnoses for Ectopic Intracerebral Calcifications.","authors":"Changrui Xiao, Thomas Cassini, Daniel Benavides, Anusha Ebrahim, David Adams, Camilo Toro","doi":"10.1212/NXG.0000000000200083","DOIUrl":"10.1212/NXG.0000000000200083","url":null,"abstract":"<p><strong>Background and objectives: </strong>Ectopic intracerebral calcifications (EICs) in the basal ganglia, thalamus, cerebellum, or white matter are seen in a variety of disease states or may be found incidentally on brain imaging. The clinical significance and proportion of cases attributable to an underlying genetic cause is unknown.</p><p><strong>Methods: </strong>This retrospective cohort study details the clinical, imaging, and genomic findings of 44 patients with EICs who had no established diagnosis despite extensive medical workup.</p><p><strong>Results: </strong>In total, 15 of 44 patients received a diagnosis through genomic testing explaining their calcifications, and 2 more received a diagnosis that has not been previously associated with EICs. Six of the 15 were found to have one of the 4 genes (<i>PDGFB</i>, <i>PDGFRB</i>, <i>SLC20A2</i>, and <i>XPR1</i>) conventionally associated with the phenotypic term \"idiopathic basal ganglia calcifications.\"</p><p><strong>Discussion: </strong>These findings support the use of genomic testing for symptomatic patients with EICs.</p>","PeriodicalId":48613,"journal":{"name":"Neurology-Genetics","volume":"9 5","pages":"e200083"},"PeriodicalIF":3.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10399077/pdf/NXG-2023-000175.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10006868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}