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Watson S, Ngo KJ, Stevens HA, Wong DY, Kim J, Song Y, Han B, Hyun SI, Khang R, Ryu SW, Lee E, Seo G, Lee H, Lajonchere C, Fogel BL. Cross-Sectional Analysis of Exome Sequencing Diagnosis in Patients With Neurologic Phenotypes Facing Barriers to Clinical Testing. Neurol Genet 2024; 10:e200133. [PMID: 38617022 PMCID: PMC11010248 DOI: 10.1212/nxg.0000000000200133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 01/19/2024] [Indexed: 04/16/2024]
Abstract
Background and Objectives Exome sequencing (ES) demonstrates a 20-50 percent diagnostic yield for patients with a suspected monogenic neurologic disease. Despite the proven efficacy in achieving a diagnosis for such patients, multiple barriers for obtaining exome sequencing remain. This study set out to assess the efficacy of ES in patients with primary neurologic phenotypes who were appropriate candidates for testing but had been unable to pursue clinical testing. Methods A total of 297 patients were identified from the UCLA Clinical Neurogenomics Research Center Biobank, and ES was performed, including bioinformatic assessment of copy number variation and repeat expansions. Information regarding demographics, clinical indication for ES, and reason for not pursuing ES clinically were recorded. To assess diagnostic efficacy, variants were interpreted by a multidisciplinary team of clinicians, bioinformaticians, and genetic counselors in accordance with the American College of Medical Genetics and Genomics variant classification guidelines. We next examined the specific barriers to testing for these patients, including how frequently insurance-related barriers such as coverage denials and inadequate coverage of cost were obstacles to pursuing exome sequencing. Results The cohort primarily consisted of patients with sporadic conditions (n = 126, 42.4%) of adult-onset (n = 239, 80.5%). Cerebellar ataxia (n = 225, 75.8%) was the most common presenting neurologic phenotype. Our study found that in this population of mostly adult patients with primary neurologic phenotypes that were unable to pursue exome sequencing clinically, 47 (15.8%) had diagnostic results while an additional 24 patients (8.1%) had uncertain results. Of the 297 patients, 206 were initially recommended for clinical exome but 88 (42.7%) could not pursue ES because of insurance barriers, of whom 14 (15.9%) had diagnostic findings, representing 29.8% of all patients with diagnostic findings. In addition, the incorporation of bioinformatic repeat expansion testing was valuable, identifying a total of 8 pathogenic repeat expansions (17.0% of all diagnostic findings) including 3 of the common spinocerebellar ataxias and 2 patients with Huntington disease. Discussion These findings underscore the importance and value of clinical ES as a diagnostic tool for neurogenetic disease and highlight key barriers that prevent patients from receiving important clinical information with potential treatment and psychosocial implications for patients and family members.
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Affiliation(s)
- Sonya Watson
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Kathie J Ngo
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Hannah A Stevens
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Darice Y Wong
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Jihye Kim
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Yongjun Song
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Beomman Han
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Seong-In Hyun
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Rin Khang
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Seung Woo Ryu
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Eugene Lee
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Gohun Seo
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Hane Lee
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Clara Lajonchere
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
| | - Brent L Fogel
- From the Department of Neurology (S.W., K.J.N., H.A.S., D.Y.W., C.L., B.L.F.), the Clinical Neurogenomics Research Center (S.W., H.A.S., D.Y.W., C.L., B.L.F.), the Institute for Precision Health (S.W., C.L., B.L.F.), and the Department of Human Genetics (S.W., B.L.F.), David Geffen School of Medicine, University of California at Los Angeles (UCLA); 3billion, Inc. (J.K., Y.S., B.H., S.-I.H., R.K., S.W.R., E.L., G.S., H.L.)
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Vizcarra JA, Paul RA, Hamedani AG, Lynch DR, Aamodt WW. Clinical Reasoning: A 48-Year-Old Man With Spasticity and Progressive Ataxia. Neurology 2023; 101:e1747-e1752. [PMID: 37596043 PMCID: PMC10624484 DOI: 10.1212/wnl.0000000000207658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 06/02/2023] [Indexed: 08/20/2023] Open
Abstract
A 48-year-old man was referred to the movement disorders clinic for 10 years of progressive slurred speech, spasticity, limb incoordination, and wide-based gait. Extensive neurologic workup was inconclusive, including serum and CSF testing, neuroimaging, EMG/NCS, exome sequencing, and mitochondrial testing. An ataxia repeat expansion panel ultimately revealed the final diagnosis. In this report, we review the clinical characteristics of a rare, late-onset, autosomal recessive cerebellar ataxia and discuss the importance of pursuing targeted gene testing to avoid diagnostic delays, especially as new treatments for this and other genetic diseases become available.
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Affiliation(s)
- Joaquin A Vizcarra
- From the Department of Neurology (J.A.V.), Emory University School of Medicine, Atlanta; Departments of Neurology (R.A.P., A.G.H., D.R.L., W.W.A.) and Ophthalmology (A.G.H.), University of Pennsylvania Perelman School of Medicine, Philadelphia; and Division of Neurology (D.R.L.), Department of Pediatrics, Children's Hospital of Philadelphia, PA
| | - Rachel A Paul
- From the Department of Neurology (J.A.V.), Emory University School of Medicine, Atlanta; Departments of Neurology (R.A.P., A.G.H., D.R.L., W.W.A.) and Ophthalmology (A.G.H.), University of Pennsylvania Perelman School of Medicine, Philadelphia; and Division of Neurology (D.R.L.), Department of Pediatrics, Children's Hospital of Philadelphia, PA
| | - Ali G Hamedani
- From the Department of Neurology (J.A.V.), Emory University School of Medicine, Atlanta; Departments of Neurology (R.A.P., A.G.H., D.R.L., W.W.A.) and Ophthalmology (A.G.H.), University of Pennsylvania Perelman School of Medicine, Philadelphia; and Division of Neurology (D.R.L.), Department of Pediatrics, Children's Hospital of Philadelphia, PA
| | - David R Lynch
- From the Department of Neurology (J.A.V.), Emory University School of Medicine, Atlanta; Departments of Neurology (R.A.P., A.G.H., D.R.L., W.W.A.) and Ophthalmology (A.G.H.), University of Pennsylvania Perelman School of Medicine, Philadelphia; and Division of Neurology (D.R.L.), Department of Pediatrics, Children's Hospital of Philadelphia, PA
| | - Whitley W Aamodt
- From the Department of Neurology (J.A.V.), Emory University School of Medicine, Atlanta; Departments of Neurology (R.A.P., A.G.H., D.R.L., W.W.A.) and Ophthalmology (A.G.H.), University of Pennsylvania Perelman School of Medicine, Philadelphia; and Division of Neurology (D.R.L.), Department of Pediatrics, Children's Hospital of Philadelphia, PA.
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Jiang L, Zhu W, Zhao G, Cao L. Spinocerebellar ataxia type 8 presents as progressive supranuclear palsy. NEUROSCIENCES (RIYADH, SAUDI ARABIA) 2023; 28:199-203. [PMID: 37482381 PMCID: PMC10519649 DOI: 10.17712/nsj.2023.3.20230032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 06/22/2023] [Accepted: 06/26/2019] [Indexed: 07/25/2023]
Abstract
Spinocerebellar ataxia type 8 is a progressive neurodegenerative disease induced by expansion of CTA/CTG repeats in an untranslated region of the ATXN8/ATXN8OS gene. We report an elderly female patient presenting with rigidity, bradykinesia, ataxia and oculomotor defect at the disease onset age of 65 years old without family history, and hummingbird sign in cranial MRI, initially diagnosed as progressive supranuclear palsy (PSP). But genetic test showed that one allele of ATXN8OS gene had more than 131 CTA/CTG repeats which was a full penetrance mutant. It's possible that this is a case of PSP with an ATXN8OS gene mutation that doesn't contribute to the phenotype. Whether the ATXN8OS gene CTA/CTG repeats cause PSP phenotype needs further investigation with larger samples and pathological findings.
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Affiliation(s)
- Lina Jiang
- From the Department of Radiology (Jiang), Department of Clinical Laboratory (Zhu), and from the Department of Neurology (Zhao, Cao), the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
| | - Weigang Zhu
- From the Department of Radiology (Jiang), Department of Clinical Laboratory (Zhu), and from the Department of Neurology (Zhao, Cao), the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
| | - Guohua Zhao
- From the Department of Radiology (Jiang), Department of Clinical Laboratory (Zhu), and from the Department of Neurology (Zhao, Cao), the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
| | - Lanxiao Cao
- From the Department of Radiology (Jiang), Department of Clinical Laboratory (Zhu), and from the Department of Neurology (Zhao, Cao), the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
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Identification of Genetic Risk Factors of Severe COVID-19 Using Extensive Phenotypic Data: A Proof-of-Concept Study in a Cohort of Russian Patients. Genes (Basel) 2022; 13:genes13030534. [PMID: 35328087 PMCID: PMC8949130 DOI: 10.3390/genes13030534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/13/2022] [Accepted: 03/14/2022] [Indexed: 11/17/2022] Open
Abstract
The COVID-19 pandemic has drawn the attention of many researchers to the interaction between pathogen and host genomes. Over the last two years, numerous studies have been conducted to identify the genetic risk factors that predict COVID-19 severity and outcome. However, such an analysis might be complicated in cohorts of limited size and/or in case of limited breadth of genome coverage. In this work, we tried to circumvent these challenges by searching for candidate genes and genetic variants associated with a variety of quantitative and binary traits in a cohort of 840 COVID-19 patients from Russia. While we found no gene- or pathway-level associations with the disease severity and outcome, we discovered eleven independent candidate loci associated with quantitative traits in COVID-19 patients. Out of these, the most significant associations correspond to rs1651553 in MYH14p = 1.4 × 10-7), rs11243705 in SETX (p = 8.2 × 10-6), and rs16885 in ATXN1 (p = 1.3 × 10-5). One of the identified variants, rs33985936 in SCN11A, was successfully replicated in an independent study, and three of the variants were found to be associated with blood-related quantitative traits according to the UK Biobank data (rs33985936 in SCN11A, rs16885 in ATXN1, and rs4747194 in CDH23). Moreover, we show that a risk score based on these variants can predict the severity and outcome of hospitalization in our cohort of patients. Given these findings, we believe that our work may serve as proof-of-concept study demonstrating the utility of quantitative traits and extensive phenotyping for identification of genetic risk factors of severe COVID-19.
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Diagnostic and Therapeutic Challengess. Retina 2021; 41:1786-1789. [PMID: 33323900 DOI: 10.1097/iae.0000000000003035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Paulus-Andres JA, Burnett MS. Three Adult-Onset Autosomal Recessive Ataxias: What Adult Neurologists Need to Know. Neurol Clin Pract 2021; 11:256-262. [PMID: 34484893 PMCID: PMC8382373 DOI: 10.1212/cpj.0000000000000947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/07/2020] [Indexed: 11/15/2022]
Abstract
PURPOSE OF REVIEW In this review we seek to raise awareness of 3 autosomal recessive ataxias that look different clinically when presenting in adulthood rather than childhood. RECENT FINDINGS A study found a high allelic frequency for repeat expansions in the RFC1 gene, a cause of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome, which presents exclusively in adults. This implies that autosomal recessive etiologies of adult-onset cerebellar ataxias may be more common than previously thought. SUMMARY Adult-onset cerebellar ataxias are commonly caused by mutations inherited in either an autosomal dominant or X-linked pattern, as most autosomal recessive mutations cause disease at earlier ages. However, some autosomal recessive etiologies such as late-onset Tay-Sachs disease, very late-onset Friedreich ataxia, and autosomal recessive spastic ataxia of Charlevoix-Saguenay emerge in adulthood, with age at presentation influencing the progression and clinical signs of the disease. This review will cover the genetics, clinical presentation, and necessary diagnostic steps required to identify 3 causes of autosomal recessive cerebellar ataxia that manifest differently in adults vs children.
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Affiliation(s)
- Jordan A Paulus-Andres
- Creighton University School of Medicine (JAP-A); and Department of Neurology (MSB), Creighton University School of Medicine, Omaha, NE
| | - Melinda S Burnett
- Creighton University School of Medicine (JAP-A); and Department of Neurology (MSB), Creighton University School of Medicine, Omaha, NE
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Hommersom MP, Buijsen RAM, van Roon-Mom WMC, van de Warrenburg BPC, van Bokhoven H. Human Induced Pluripotent Stem Cell-Based Modelling of Spinocerebellar Ataxias. Stem Cell Rev Rep 2021; 18:441-456. [PMID: 34031815 PMCID: PMC8930896 DOI: 10.1007/s12015-021-10184-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2021] [Indexed: 12/13/2022]
Abstract
Abstract Dominant spinocerebellar ataxias (SCAs) constitute a large group of phenotypically and genetically heterogeneous disorders that mainly present with dysfunction of the cerebellum as their main hallmark. Although animal and cell models have been highly instrumental for our current insight into the underlying disease mechanisms of these neurodegenerative disorders, they do not offer the full human genetic and physiological context. The advent of human induced pluripotent stem cells (hiPSCs) and protocols to differentiate these into essentially every cell type allows us to closely model SCAs in a human context. In this review, we systematically summarize recent findings from studies using hiPSC-based modelling of SCAs, and discuss what knowledge has been gained from these studies. We conclude that hiPSC-based models are a powerful tool for modelling SCAs as they contributed to new mechanistic insights and have the potential to serve the development of genetic therapies. However, the use of standardized methods and multiple clones of isogenic lines are essential to increase validity and reproducibility of the insights gained. Graphical Abstract ![]()
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Affiliation(s)
- Marina P Hommersom
- Department of Human Genetics, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
| | - Ronald A M Buijsen
- Department of Human Genetics, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Willeke M C van Roon-Mom
- Department of Human Genetics, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Bart P C van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands.
| | - Hans van Bokhoven
- Department of Human Genetics, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands. .,Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB, Nijmegen, Netherlands.
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Koebley SR, Mikheikin A, Leslie K, Guest D, McConnell-Wells W, Lehman JH, Al Juhaishi T, Zhang X, Roberts CH, Picco L, Toor A, Chesney A, Reed J. Digital Polymerase Chain Reaction Paired with High-Speed Atomic Force Microscopy for Quantitation and Length Analysis of DNA Length Polymorphisms. ACS NANO 2020; 14:15385-15393. [PMID: 33169971 DOI: 10.1021/acsnano.0c05897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
DNA length polymorphisms are found in many serious diseases, and assessment of their length and abundance is often critical for accurate diagnosis. However, measuring their length and frequency in a mostly wild-type background, as occurs in many situations, remains challenging due to their variable and repetitive nature. To overcome these hurdles, we combined two powerful techniques, digital polymerase chain reaction (dPCR) and high-speed atomic force microscopy (HSAFM), to create a simple, rapid, and flexible method for quantifying both the size and proportion of DNA length polymorphisms. In our approach, individual amplicons from each dPCR partition are imaged and sized directly. We focused on internal tandem duplications (ITDs) located within the FLT3 gene, which are associated with acute myeloid leukemia and often indicative of a poor prognosis. In an analysis of over 1.5 million HSAFM-imaged amplicons from cell line and clinical samples containing FLT3-ITDs, dPCR-HSAFM returned the expected variant length and variant allele frequency, down to 5% variant samples. As a high-throughput method with single-molecule resolution, dPCR-HSAFM thus represents an advance in HSAFM analysis and a powerful tool for the diagnosis of length polymorphisms.
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Affiliation(s)
- Sean R Koebley
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Andrey Mikheikin
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Kevin Leslie
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Daniel Guest
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Wendy McConnell-Wells
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Joshua H Lehman
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Taha Al Juhaishi
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Xiaojie Zhang
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Catherine H Roberts
- Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Loren Picco
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Amir Toor
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Alden Chesney
- Department of Pathology, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Jason Reed
- Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284, United States
- Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298, United States
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Perez Maturo J, Zavala L, Vega P, González-Morón D, Medina N, Salinas V, Rosales J, Córdoba M, Arakaki T, Garretto N, Rodríguez-Quiroga S, Kauffman MA. Overwhelming genetic heterogeneity and exhausting molecular diagnostic process in chronic and progressive ataxias: facing it up with an algorithm, a gene, a panel at a time. J Hum Genet 2020; 65:895-902. [DOI: 10.1038/s10038-020-0785-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/18/2022]
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Aboud Syriani D, Wong D, Andani S, De Gusmao CM, Mao Y, Sanyoura M, Glotzer G, Lockhart PJ, Hassin-Baer S, Khurana V, Gomez CM, Perlman S, Das S, Fogel BL. Prevalence of RFC1-mediated spinocerebellar ataxia in a North American ataxia cohort. NEUROLOGY-GENETICS 2020; 6:e440. [PMID: 32582864 PMCID: PMC7274910 DOI: 10.1212/nxg.0000000000000440] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 03/15/2020] [Indexed: 12/15/2022]
Abstract
Objective We evaluated the prevalence of pathogenic repeat expansions in replication factor C subunit 1 (RFC1) and disabled adaptor protein 1 (DAB1) in an undiagnosed ataxia cohort from North America. Methods A cohort of 596 predominantly adult-onset patients with undiagnosed familial or sporadic cerebellar ataxia was evaluated at a tertiary referral ataxia center and excluded for common genetic causes of cerebellar ataxia. Patients were then screened for the presence of pathogenic repeat expansions in RFC1 (AAGGG) and DAB1 (ATTTC) using fluorescent repeat-primed PCR (RP-PCR). Two additional undiagnosed ataxia cohorts from different centers, totaling 302 and 13 patients, respectively, were subsequently screened for RFC1, resulting in a combined 911 subjects tested. Results In the initial cohort, 41 samples were identified with 1 expanded allele in the RFC1 gene (6.9%), and 9 had 2 expanded alleles (1.5%). For the additional cohorts, we found 20 heterozygous samples (6.6%) and 17 biallelic samples (5.6%) in the larger cohort and 1 heterozygous sample (7.7%) and 3 biallelic samples (23%) in the second. In total, 29 patients were identified with biallelic repeat expansions in RFC1 (3.2%). Of these 29 patients, 8 (28%) had a clinical diagnosis of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS), 14 had cerebellar ataxia with neuropathy (48%), 4 had pure cerebellar ataxia (14%), and 3 had spinocerebellar ataxia (10%). No patients were identified with expansions in the DAB1 gene (spinocerebellar ataxia type 37). Conclusions In a large undiagnosed ataxia cohort from North America, biallelic pathogenic repeat expansion in RFC1 was observed in 3.2%. Testing should be strongly considered in patients with ataxia, especially those with CANVAS or neuropathy.
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Affiliation(s)
- Dona Aboud Syriani
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Darice Wong
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Sameer Andani
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Claudio M De Gusmao
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Yuanming Mao
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - May Sanyoura
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Giacomo Glotzer
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Paul J Lockhart
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Sharon Hassin-Baer
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Vikram Khurana
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Christopher M Gomez
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Susan Perlman
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Soma Das
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
| | - Brent L Fogel
- Department of Neurology (D.A.S., D.W., Y.M., S.P., B.L.F.), Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles; Department of Neurology (D.W., B.L.F.), Clinical Neurogenomics Research Center, David Geffen School of Medicine, University of California, Los Angeles; Department of Human Genetics (S.A., M.S., S.D.), University of Chicago, IL; Department of Neurology (C.M.D.G., V.K.), Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Department of Neurology (G.G., C.M.G.), University of Chicago, IL; Bruce Lefroy Centre (P.J.L.), Murdoch Children's Research Institute; Department of Paediatrics (P.J.L.), University of Melbourne, Parkville, Australia; Sackler Faculty of Medicine (S.H.-B.), Tel-Aviv University, Tel-Aviv, Israel; and Department of Human Genetics (B.L.F.), David Geffen School of Medicine, University of California, Los Angeles
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Mitchell N, LaTouche GA, Nelson B, Figueroa KP, Walker RH, Sobering AK. Childhood-Onset Spinocerebellar Ataxia 3: Tongue Dystonia as an Early Manifestation. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2019; 9:tre-09-704. [PMID: 31565539 PMCID: PMC6744815 DOI: 10.7916/tohm.v0.704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 08/12/2019] [Indexed: 12/01/2022]
Abstract
Background Dystonia is a relatively common feature of spinocerebellar ataxia 3 (SCA3). Childhood onset of SCA3 is rare and typically associated with either relatively large, or homozygous, CAG repeat expansions. Case report We describe a 10-year-old girl with SCA3, who presented with tongue dystonia in addition to limb dystonia and gait ataxia due to a heterozygous expansion of 84 repeats in ATXN3. Discussion Diagnosis of the SCAs can be challenging, and even more so in children. Tongue dystonia has not previously been documented in SCA3.
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Affiliation(s)
- Nester Mitchell
- Department of Internal Medicine, Grenada General Hospital, St. George's, GD
| | - Gaynel A LaTouche
- Department of Internal Medicine, Grenada General Hospital, St. George's, GD
| | - Beverly Nelson
- Department of Internal Medicine, Grenada General Hospital, St. George's, GD
| | - Karla P Figueroa
- Department of Pediatrics, Grenada General Hospital, St. George's, GD
| | - Ruth H Walker
- Department of Neurology, University of Utah, Salt Lake City, UT, USA.,Department of Neurology, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA
| | - Andrew K Sobering
- Department of Neurology, Mount Sinai School of Medicine, New York City, NY, USA
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12
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Truncating SLC12A6 variants cause different clinical phenotypes in humans and dogs. Eur J Hum Genet 2019; 27:1561-1568. [PMID: 31160700 DOI: 10.1038/s41431-019-0432-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/06/2019] [Accepted: 05/14/2019] [Indexed: 12/13/2022] Open
Abstract
Clinical, pathological, and genetic findings of a primary hereditary ataxia found in a Malinois dog family are described and compared with its human counterpart. Based on the family history and the phenotype/genotype relationships already described in humans and dogs, a causal variant was expected to be found in KCNJ10. Rather surprisingly, whole-exome sequencing identified the SLC12A6 NC_006612.3(XM_014109414.2): c.178_181delinsCATCTCACTCAT (p.(Met60Hisfs*14)) truncating variant. This loss-of-function variant perfectly segregated within the affected Malinois family in an autosomal recessive way and was not found in 562 additional reference dogs from 18 different breeds, including Malinois. In humans, SLC12A6 variants cause "agenesis of the corpus callosum with peripheral neuropathy" (ACCPN, alias Andermann syndrome), owing to a dysfunction of this K+-Cl- cotransporter. However, depending on the variant (including truncating variants), different clinical features are observed within ACCPN. The variant in dogs encodes the shortest isoform described so far and its resultant phenotype is quite different from humans, as no signs of peripheral neuropathy, agenesis of the corpus callosum nor obvious mental retardation have been observed in dogs. On the other hand, progressive spinocerebellar ataxia, which is the most important feature of the canine phenotype, hindlimb paresis, and myokymia-like muscle contractions have not been described in humans with ACCPN so far. As this is the first report of a naturally occurring disease-causing SLC12A6 variant in a non-human species, the canine model will be highly valuable to better understand the complex molecular pathophysiology of SLC12A6-related neurological disorders and to evaluate novel treatment strategies.
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Yearwood AK, Rethi S, Figueroa KP, Walker RH, Sobering AK. Diagnosis of Spinocerebellar Ataxia in the West Indies. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2018; 8:567. [PMID: 30191086 PMCID: PMC6123834 DOI: 10.7916/d8dv329c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 06/07/2018] [Indexed: 12/11/2022]
Abstract
Background Access to medical care in many regions is limited by socioeconomic status, at both the individual and the community level. This report describes the diagnostic process of a family residing on an underserved Caribbean island where routine neurological care is typically addressed by general practitioners, and genetic diagnosis is not available through regular medical channels. The diagnosis and management of neurodegenerative disorders is especially challenging in this setting. Case Report We diagnosed a family with spinocerebellar ataxia type 3 (SCA3) in an underdeveloped nation with limited access to genetic medicine and no full-time neurologist. Discussion Molecular diagnosis of the SCAs can be challenging, even in developed countries. In the Caribbean, genetic testing is generally only available at a small number of academic centers. Diagnosis in this family was ultimately made by utilizing an international, pro bono, research-based collaborative process. Although access to appropriate resources, such as speech, physical, and occupational therapies, is limited on this island because of economic and geographical factors, the provision of a diagnosis appeared to be ultimately beneficial for this family. Identification of affected families highlights the need for access to genetic diagnosis in all communities, and can help direct resources where needed.
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Affiliation(s)
- Ashley K Yearwood
- Department of Biochemistry, St. George's University, St. George's, Grenada, West Indies
| | - Shruthi Rethi
- Department of Biochemistry, St. George's University, St. George's, Grenada, West Indies
| | - Karla P Figueroa
- University of Utah, Department of Neurology, Salt Lake City, UT, USA
| | - Ruth H Walker
- Department of Neurology, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA.,Department of Neurology, Mount Sinai School of Medicine, New York City, NY, USA
| | - Andrew K Sobering
- Department of Biochemistry, St. George's University, St. George's, Grenada, West Indies
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Paciorkowski AR. Ode to the humble Southern blot in the era of exomes. Neurol Clin Pract 2018. [DOI: 10.1212/cpj.0000000000000414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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