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van der Geest MA, Maeckelberghe ELM, van Gijn ME, Lucassen AM, Swertz MA, van Langen IM, Plantinga M. Systematic reanalysis of genomic data by diagnostic laboratories: a scoping review of ethical, economic, legal and (psycho)social implications. Eur J Hum Genet 2024; 32:489-497. [PMID: 38480795 PMCID: PMC11061183 DOI: 10.1038/s41431-023-01529-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 12/11/2023] [Accepted: 12/19/2023] [Indexed: 05/02/2024] Open
Abstract
With the introduction of Next Generation Sequencing (NGS) techniques increasing numbers of disease-associated variants are being identified. This ongoing progress might lead to diagnoses in formerly undiagnosed patients and novel insights in already solved cases. Therefore, many studies suggest introducing systematic reanalysis of NGS data in routine diagnostics. Introduction will, however, also have ethical, economic, legal and (psycho)social (ELSI) implications that Genetic Health Professionals (GHPs) from laboratories should consider before possible implementation of systematic reanalysis. To get a first impression we performed a scoping literature review. Our findings show that for the vast majority of included articles ELSI aspects were not mentioned as such. However, often these issues were raised implicitly. In total, we identified nine ELSI aspects, such as (perceived) professional responsibilities, implications for consent and cost-effectiveness. The identified ELSI aspects brought forward necessary trade-offs for GHPs to consciously take into account when considering responsible implementation of systematic reanalysis of NGS data in routine diagnostics, balancing the various strains on their laboratories and personnel while creating optimal results for new and former patients. Some important aspects are not well explored yet. For example, our study shows GHPs see the values of systematic reanalysis but also experience barriers, often mentioned as being practical or financial only, but in fact also being ethical or psychosocial. Engagement of these GHPs in further research on ELSI aspects is important for sustainable implementation.
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Affiliation(s)
- Marije A van der Geest
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Els L M Maeckelberghe
- Institute for Medical Education, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Marielle E van Gijn
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Anneke M Lucassen
- Faculty of Medicine, Clinical Ethics and Law, University of Southampton, Southampton, UK
- Centre for Personalised Medicine, Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Morris A Swertz
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Irene M van Langen
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Mirjam Plantinga
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Azuelos C, Marquis MA, Laberge AM. A systematic review of the assessment of the clinical utility of genomic sequencing: Implications of the lack of standard definitions and measures of clinical utility. Eur J Med Genet 2024; 68:104925. [PMID: 38432472 DOI: 10.1016/j.ejmg.2024.104925] [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: 09/21/2023] [Revised: 12/31/2023] [Accepted: 02/11/2024] [Indexed: 03/05/2024]
Abstract
PURPOSE Exome sequencing (ES) and genome sequencing (GS) are diagnostic tests for rare genetic diseases. Studies report clinical utility of ES/GS. The goal of this systematic review is to establish how clinical utility is defined and measured in studies evaluating the impacts of ES/GS results for pediatric patients. METHODS Relevant articles were identified in PubMed, Medline, Embase, and Web of Science. Eligible studies assessed clinical utility of ES/GS for pediatric patients published before 2021. Other relevant articles were added based on articles' references. Articles were coded to assess definitions and measures of clinical utility. RESULTS Of 1346 articles, 83 articles met eligibility criteria. Clinical utility was not clearly defined in 19% of studies and 92% did not use an explicit measure of clinical utility. When present, definitions of clinical utility diverged from recommended definitions and varied greatly, from narrow (diagnostic yield of ES/GS) to broad (including decisions about withdrawal of care/palliative care and/or impacts on other family members). CONCLUSION Clinical utility is used to guide policy and practice decisions about test use. The lack of a standard definition of clinical utility of ES/GS may lead to under- or overestimations of clinical utility, complicating policymaking and raising ethical issues.
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Affiliation(s)
- Claudia Azuelos
- Medical Genetics, Dept of Pediatrics, CHU Sainte-Justine and Université de Montréal, Canada.
| | - Marc-Antoine Marquis
- Palliative Care, Dept of Pediatrics, CHU Sainte-Justine and Université de Montréal, Canada
| | - Anne-Marie Laberge
- Medical Genetics, Dept of Pediatrics, CHU Sainte-Justine and Université de Montréal, Canada.
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Rački V, Hero M, Papić E, Rožmarić G, Čizmarević NS, Chudy D, Peterlin B, Vuletić V. Applicability of clinical genetic testing for deep brain stimulation treatment in monogenic Parkinson's disease and monogenic dystonia: a multidisciplinary team perspective. Front Neurosci 2023; 17:1282267. [PMID: 38027472 PMCID: PMC10667448 DOI: 10.3389/fnins.2023.1282267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023] Open
Abstract
In this perspective article, we highlight the possible applicability of genetic testing in Parkinson's disease and dystonia patients treated with deep brain stimulation (DBS). DBS, a neuromodulatory technique employing electrical stimulation, has historically targeted motor symptoms in advanced PD and dystonia, yet its precise mechanisms remain elusive. Genetic insights have emerged as potential determinants of DBS efficacy. Known PD genes such as GBA, SNCA, LRRK2, and PRKN are most studied, even though further studies are required to make firm conclusions. Variable outcomes depending on genotype is present in genetic dystonia, as DYT-TOR1A, NBIA/DYTPANK2, DYT-SCGE and X-linked dystonia-parkinsonism have demonstrated promising outcomes following GPi-DBS, while varying outcomes have been documented in DYT-THAP1. We present two clinical vignettes that illustrate the applicability of genetics in clinical practice, with one PD patient with compound GBA mutations and one GNAL dystonia patient. Integrating genetic testing into clinical practice is pivotal, particularly with advancements in next-generation sequencing. However, there is a clear need for further research, especially in rarer monogenic forms. Our perspective is that applying genetics in PD and dystonia is possible today, and despite challenges, it has the potential to refine patient selection and enhance treatment outcomes.
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Affiliation(s)
- Valentino Rački
- Department of Neurology, Clinical Hospital Center Rijeka, Rijeka, Croatia
- Department of Neurology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Mario Hero
- Department of Neurology, Clinical Hospital Center Rijeka, Rijeka, Croatia
- Department of Neurology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Eliša Papić
- Department of Neurology, Clinical Hospital Center Rijeka, Rijeka, Croatia
- Department of Neurology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Gloria Rožmarić
- Department of Neurology, Clinical Hospital Center Rijeka, Rijeka, Croatia
| | - Nada Starčević Čizmarević
- Department of Medical Genomics and Biology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Darko Chudy
- Department of Neurosurgery, Clinical Hospital Dubrava, Zagreb, Croatia
| | - Borut Peterlin
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Vladimira Vuletić
- Department of Neurology, Clinical Hospital Center Rijeka, Rijeka, Croatia
- Department of Neurology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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Yao L, Zhu Z, Zhang C, Tian W, Cao L. PLP1 gene mutations cause spastic paraplegia type 2 in three families. Ann Clin Transl Neurol 2023; 10:328-338. [PMID: 36622199 PMCID: PMC10014006 DOI: 10.1002/acn3.51722] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE Spastic paraplegia type 2 (SPG2) is an X-linked recessive (XLR) form of hereditary spastic paraplegia (HSP) caused by mutations in proteolipid protein 1 (PLP1) gene. We described the clinical and genetic features of three unrelated families with PLP1 mutations and reviewed PLP1-related cases worldwide to summarize the genotype-phenotype correlations. METHODS The three probands were 23, 26, and 27 years old, respectively, with progressively aggravated walking difficulty as well as lower limb spasticity. Detailed physical examination showed elevated muscle tone, hyperreflexia, and Babinski signs in lower limbs. Brain MRI examinations were investigated for all cases. PLP1 mutations were identified by whole exome sequencing, followed by Sanger sequencing, family co-segregation, and phenotypic reevaluation. RESULTS A total of eight patients with SPG2 were identified in these three families. The probands additionally had cognitive impairment, urinary or fecal incontinence, ataxia, and white matter lesions (WML) in periventricular regions, with or without kinetic tremor. Three hemizygous mutations in PLP1 were identified, including c.453+159G>A, c.834A>T (p.*278C), and c.434G>A (p.W145*), of which c.834A>T was first associated with HSP. INTERPRETATION We identified three families with complicated SPG2 due to three PLP1 mutations. Our study supports the clinically inter-and intra-family heterogeneity of SPG2. The periventricular region WML and cognitive impairment are the most common characteristics. The kinetic tremor in upper limbs was observed in 2/3 families, suggesting the spectrum of PLP1-related disorders is still expanding.
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Affiliation(s)
- Li Yao
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.,Suzhou Hospital of Anhui Medical University, Suzhou Municipal Hospital of Anhui Province, Suzhou, 234000, China
| | - Zeyu Zhu
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Chao Zhang
- Suzhou Hospital of Anhui Medical University, Suzhou Municipal Hospital of Anhui Province, Suzhou, 234000, China
| | - Wotu Tian
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Li Cao
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
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The emergence of genotypic divergence and future precision medicine applications. HANDBOOK OF CLINICAL NEUROLOGY 2023; 192:87-99. [PMID: 36796950 DOI: 10.1016/b978-0-323-85538-9.00013-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Genotypic divergence is a term adapted from population genetics and intimately linked to evolution. We use divergence here to emphasize the differences that set individuals apart in any cohort. The history of genetics is filled with descriptions of genotypic differences, but causal inference of interindividual biological variation has been scarce. We suggest that the practice of precision medicine requires a divergent approach, an approach dependent on the causal interpretation of previous convergent (and preliminary) knowledge in the field. This knowledge has relied on convergent descriptive syndromology (lumping), which has overemphasized a reductionistic gene determinism on the quest of seeking associations without causal understanding. Regulatory variants with small effect and somatic mutations are some of the modifying factors that lead to incomplete penetrance and intrafamilial variable expressivity often observed in apparently monogenic clinical disorders. A truly divergent approach to precision medicine requires splitting, that is, the consideration of different layers of genetic phenomena that interact causally in a nonlinear fashion. This chapter reviews convergences and divergences in genetics and genomics, aiming to discuss what can be causally understood to approximate the as-yet utopian lands of Precision Medicine for patients with neurodegenerative disorders.
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Schobers G, Schieving JH, Yntema HG, Pennings M, Pfundt R, Derks R, Hofste T, de Wijs I, Wieskamp N, van den Heuvel S, Galbany JC, Gilissen C, Nelen M, Brunner HG, Kleefstra T, Kamsteeg EJ, Willemsen MAAP, Vissers LELM. Reanalysis of exome negative patients with rare disease: a pragmatic workflow for diagnostic applications. Genome Med 2022; 14:66. [PMID: 35710456 PMCID: PMC9204949 DOI: 10.1186/s13073-022-01069-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/07/2022] [Indexed: 11/10/2022] Open
Abstract
Background Approximately two third of patients with a rare genetic disease remain undiagnosed after exome sequencing (ES). As part of our post-test counseling procedures, patients without a conclusive diagnosis are advised to recontact their referring clinician to discuss new diagnostic opportunities in due time. We performed a systematic study of genetically undiagnosed patients 5 years after their initial negative ES report to determine the efficiency of diverse reanalysis strategies. Methods We revisited a cohort of 150 pediatric neurology patients originally enrolled at Radboud University Medical Center, of whom 103 initially remained genetically undiagnosed. We monitored uptake of physician-initiated routine clinical and/or genetic re-evaluation (ad hoc re-evaluation) and performed systematic reanalysis, including ES-based resequencing, of all genetically undiagnosed patients (systematic re-evaluation). Results Ad hoc re-evaluation was initiated for 45 of 103 patients and yielded 18 diagnoses (including 1 non-genetic). Subsequent systematic re-evaluation identified another 14 diagnoses, increasing the diagnostic yield in our cohort from 31% (47/150) to 53% (79/150). New genetic diagnoses were established by reclassification of previously identified variants (10%, 3/31), reanalysis with enhanced bioinformatic pipelines (19%, 6/31), improved coverage after resequencing (29%, 9/31), and new disease-gene associations (42%, 13/31). Crucially, our systematic study also showed that 11 of the 14 further conclusive genetic diagnoses were made in patients without a genetic diagnosis that did not recontact their referring clinician. Conclusions We find that upon re-evaluation of undiagnosed patients, both reanalysis of existing ES data as well as resequencing strategies are needed to identify additional genetic diagnoses. Importantly, not all patients are routinely re-evaluated in clinical care, prolonging their diagnostic trajectory, unless systematic reanalysis is facilitated. We have translated our observations into considerations for systematic and ad hoc reanalysis in routine genetic care. Supplementary Information The online version contains supplementary material available at 10.1186/s13073-022-01069-z.
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Affiliation(s)
- Gaby Schobers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Jolanda H Schieving
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Pediatric Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Helger G Yntema
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maartje Pennings
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronny Derks
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tom Hofste
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ilse de Wijs
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nienke Wieskamp
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Simone van den Heuvel
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jordi Corominas Galbany
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Marcel Nelen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Han G Brunner
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Clinical Genetics, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michèl A A P Willemsen
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Pediatric Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lisenka E L M Vissers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands. .,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
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Marsili L, Duque KR, Bode RL, Kauffman MA, Espay AJ. Uncovering Essential Tremor Genetics: The Promise of Long-Read Sequencing. Front Neurol 2022; 13:821189. [PMID: 35401394 PMCID: PMC8983820 DOI: 10.3389/fneur.2022.821189] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/25/2022] [Indexed: 12/23/2022] Open
Abstract
Long-read sequencing (LRS) technologies have been recently introduced to overcome intrinsic limitations of widely-used next-generation sequencing (NGS) technologies, namely the sequencing limited to short-read fragments (150–300 base pairs). Since its introduction, LRS has permitted many successes in unraveling hidden mutational mechanisms. One area in clinical neurology in need of rethinking as it applies to genetic mechanisms is essential tremor (ET). This disorder, among the most common in neurology, is a syndrome often exhibiting an autosomal dominant pattern of inheritance whose large phenotypic spectrum suggest a multitude of genetic etiologies. Exome sequencing has revealed the genetic etiology only in rare ET families (FUS, SORT1, SCN4A, NOS3, KCNS2, HAPLN4/BRAL2, and USP46). We hypothesize that a reason for this shortcoming may be non-classical genetic mechanism(s) underpinning ET, among them trinucleotide, tetranucleotide, or pentanucleotide repeat disorders. In support of this hypothesis, trinucleotide (e.g., GGC repeats in NOTCH2NLC) and pentanucleotide repeat disorders (e.g., ATTTC repeats in STARD7) have been revealed as pathogenic in patients with a past history of what has come to be referred to as “ET plus,” bilateral hand tremor associated with epilepsy and/or leukoencephalopathy. A systematic review of LRS in neurodegenerative disorders showed that 10 of the 22 (45%) genetic etiologies ascertained by LRS include tremor in their phenotypic spectrum, suggesting that future clinical applications of LRS for tremor disorders may uncover genetic subtypes of familial ET that have eluded NGS, particularly those with associated leukoencephalopathy or family history of epilepsy. LRS provides a pathway for potentially uncovering novel genes and genetic mechanisms, helping narrow the large proportion of “idiopathic” ET.
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Affiliation(s)
- Luca Marsili
- James J. and Joan A. Gardner Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, OH, United States
| | - Kevin R. Duque
- James J. and Joan A. Gardner Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, OH, United States
| | - Rachel L. Bode
- James J. and Joan A. Gardner Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, OH, United States
| | - Marcelo A. Kauffman
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología José María Ramos Mejía, Buenos Aires, Argentina
| | - Alberto J. Espay
- James J. and Joan A. Gardner Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, OH, United States
- *Correspondence: Alberto J. Espay
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Methods to Improve Molecular Diagnosis in Genomic Cold Cases in Pediatric Neurology. Genes (Basel) 2022; 13:genes13020333. [PMID: 35205378 PMCID: PMC8871714 DOI: 10.3390/genes13020333] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 02/04/2023] Open
Abstract
During the last decade, genetic testing has emerged as an important etiological diagnostic tool for Mendelian diseases, including pediatric neurological conditions. A genetic diagnosis has a considerable impact on disease management and treatment; however, many cases remain undiagnosed after applying standard diagnostic sequencing techniques. This review discusses various methods to improve the molecular diagnostic rates in these genomic cold cases. We discuss extended analysis methods to consider, non-Mendelian inheritance models, mosaicism, dual/multiple diagnoses, periodic re-analysis, artificial intelligence tools, and deep phenotyping, in addition to integrating various omics methods to improve variant prioritization. Last, novel genomic technologies, including long-read sequencing, artificial long-read sequencing, and optical genome mapping are discussed. In conclusion, a more comprehensive molecular analysis and a timely re-analysis of unsolved cases are imperative to improve diagnostic rates. In addition, our current understanding of the human genome is still limited due to restrictions in technologies. Novel technologies are now available that improve upon some of these limitations and can capture all human genomic variation more accurately. Last, we recommend a more routine implementation of high molecular weight DNA extraction methods that is coherent with the ability to use and/or optimally benefit from these novel genomic methods.
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Xu X, Lu F, Du S, Zhao X, Li H, Zhang L, Tang J. Case report: Novel compound heterozygous missense mutations in the DDHD2 gene in a Chinese patient associated with spastic paraplegia type 54. Front Pediatr 2022; 10:997274. [PMID: 36090575 PMCID: PMC9458848 DOI: 10.3389/fped.2022.997274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/10/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Spastic paraplegia type 54 (SPG54) is a rare inherited autosomal recessive disorder, and a complex hereditary spastic paraplegia (HSP) caused by mutations in the phospholipase DDHD2 gene. SPG54 is characterized by early onset of spastic paraplegia, intellectual disability and dysplasia of corpus callosum. CASE PRESENTATION We report a 9 years and 5 months old Chinese girl with progressive spasm of the lower limbs, muscle weakness and intellectual disability. Brain magnetic resonance imaging (MRI) showed periventricular leukomalacia and thinning of the corpus callosum. According to the Wechsler Intelligence Scale, her IQ is 42. By whole exome sequencing, novel compound heterozygous missense mutations in the DDHD2 gene [c.168G>C, p.(Trp56Cys) and c.1505T>C, p.(Phe502Ser)] were identified in the proband. Comparative amino acid sequence alignment across different species revealed that Trp56 and Phe502 in the DDHD2 protein were highly conserved during evolution. And multiple in silico prediction tools suggested that both mutations were deleterious. CONCLUSIONS Our study reports a very rare case of complicated HSP caused by two novel compound heterozygous mutations in the DDHD2 gene. Our findings expand the genetic spectrum of SPG54.
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Affiliation(s)
- Xin Xu
- Department of Rehabilitation, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Fen Lu
- Department of Rehabilitation, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Senjie Du
- Department of Rehabilitation, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Xiaoke Zhao
- Department of Rehabilitation, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Hongying Li
- Department of Rehabilitation, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Li Zhang
- Department of Rehabilitation, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jian Tang
- Department of Rehabilitation, Children's Hospital of Nanjing Medical University, Nanjing, China
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Prada CE, Cavalcanti D, Schwartz IVD, Zarate YA. Introduction to the special issue on Clinical Genetics in Latin America. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:873-875. [PMID: 33354820 DOI: 10.1002/ajmg.c.31875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Carlos E Prada
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Denise Cavalcanti
- Medical Genetics Department, Medical Sciences Faculty, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Ida Vanessa Doederlein Schwartz
- Genetics Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Medical Genetics Service and Clinical Research Center, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil
| | - Yuri A Zarate
- Section of Genetics and Metabolism, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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