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Abstract
The presence of unprovoked, recurrent seizures, particularly when drug resistant and associated with cognitive and behavioral deficits, warrants investigation for an underlying genetic cause. This article provides an overview of the major classes of genes associated with epilepsy phenotypes divided into functional categories along with the recommended work-up and therapeutic considerations. Gene discovery in epilepsy supports counseling and anticipatory guidance but also opens the door for precision medicine guiding therapy with a focus on those with disease-modifying effects.
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Affiliation(s)
- Luis A Martinez
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Yi-Chen Lai
- Department of Pediatrics, Section of Pediatric Critical Care Medicine, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - J Lloyd Holder
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Anne E Anderson
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA.
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2
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Cesario A, Lohmeyer FM, D'Oria M, Manto A, Scambia G. The personalized medicine discourse: archaeology and genealogy. MEDICINE, HEALTH CARE, AND PHILOSOPHY 2021; 24:247-253. [PMID: 33389365 DOI: 10.1007/s11019-020-09997-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
Personalized Medicine (PM) is an evolving and often missinterpreted concept and no agreement of personalization exist. We examined the PM discourse towards foucauldian archeological and genealogical analysis to understand the meaning of "personalization" in medicine. In the archaeological analysis, the historical evolution is characterized by the coexistence of two epistemologies: the holistic vision and the omic sciences. The genealogical analysis shows how these epistemologies may affect the meaning of "person" and, consequently, the ontology of patients. Additionally, substitutions/confusions of the term PM are related to continuously evolving medical knowledge and new technologies; different etymological roots of "personalization" and "person"; and cultural differences. In conclusion, if the definition of "personalization" in medicine is not clear, patients might get wrong expectations about what is achievable for their health. Therefore, epistemological trends should not be separated as they drive same goals: providing accurate diagnosis and treatments based on large data to predict disease progression.
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Affiliation(s)
- Alfredo Cesario
- Scientific Directorate, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 8, 00168, Rome, Italy
- The Italian Association of Systems Medicine and Healthcare, Rome, Italy
| | - Franziska Michaela Lohmeyer
- Scientific Directorate, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 8, 00168, Rome, Italy
| | - Marika D'Oria
- Scientific Directorate, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 8, 00168, Rome, Italy.
| | - Andrea Manto
- Istituto Superiore di Scienze Religiose "Ecclesia Mater", Pontificia Università Lateranense, Rome, Italy
- Fondazione "Ut Vitam Habeant", Rome, Italy
| | - Giovanni Scambia
- Scientific Directorate, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 8, 00168, Rome, Italy
- Department of Gynecologic Oncology, Catholic University of the Sacred Heart, Rome, Italy
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3
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Wang F, Xiong S, Wu L, Chopra M, Hu X, Wu B. A novel TSC2 missense variant associated with a variable phenotype of tuberous sclerosis complex: case report of a Chinese family. BMC MEDICAL GENETICS 2018; 19:90. [PMID: 29843636 PMCID: PMC5975528 DOI: 10.1186/s12881-018-0611-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 05/18/2018] [Indexed: 11/10/2022]
Abstract
Background Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder characterized by the development of hamartomas in multiple organs, including the brain, heart, skin, kidney, lung and retina. A diagnosis of TSC is established with a recently revised clinical/radiological set of criteria and/or a causative mutation in TSC1 or TSC2 gene. Case presentation We report a Chinese TSC family with two siblings presenting with multiple hypomelanotic macules, cardiac rhabdomyomas and cortical tubers associated with a small subependymal nodule. The older child had seizures. A novel heterozygous missense variant in the TSC2 gene (c.899G > T, p.G300 V) was identified and shown to be inherited from their father as well as paternal grandfather, both of whom presented with variable TSC-associated signs and symptoms. Conclusion We identified a novel heterozygous TSC2 variant c.899G > T as the causative mutation in a Chinese family with TSC, resulting in wide intrafamilial phenotypic variability. Our study illustrates the importance of clinical evaluation and genetic testing for family members of the patient affected with TSC.
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Affiliation(s)
- Feng Wang
- Department of Cardiology, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, People's Republic of China
| | - Shiyi Xiong
- Fetal Medicine Unit & Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Lin Wu
- Department of Cardiology, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, People's Republic of China.
| | - Maya Chopra
- Fetal Medicine Unit & Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China.,Department of Medical Genomics, Royal Prince Alfred Hospital, Missenden Road, Sydney, NSW, Australia
| | - Xihong Hu
- Department of Radiology, Children's Hospital of Fudan University, Shanghai, People's Republic of China
| | - Bingbing Wu
- Institute of Pediatrics, Children's Hospital of Fudan University, Shanghai, People's Republic of China
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Izumi K, Hayashi D, Grochowski CM, Kubota N, Nishi E, Arakawa M, Hiroma T, Hatata T, Ogiso Y, Nakamura T, Falsey AM, Hidaka E, Spinner NB. Discordant clinical phenotype in monozygotic twins with Alagille syndrome: Possible influence of non-genetic factors. Am J Med Genet A 2015; 170A:471-475. [PMID: 26463753 DOI: 10.1002/ajmg.a.37429] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 09/27/2015] [Indexed: 11/08/2022]
Abstract
Alagille syndrome is a multisystem developmental disorder characterized by bile duct paucity, congenital heart disease, vertebral anomalies, posterior embryotoxon, and characteristic facial features. Alagille syndrome is typically the result of germline mutations in JAG1 or NOTCH2 and is one of several human diseases caused by Notch signaling abnormalities. A wide phenotypic spectrum has been well documented in Alagille syndrome. Therefore, monozygotic twins with Alagille syndrome provide a unique opportunity to evaluate potential phenotypic modifiers such as environmental factors or stochastic effects of gene expression. In this report, we describe an Alagille syndrome monozygotic twin pair with discordant placental and clinical findings. We propose that environmental factors such as prenatal hypoxia may have played a role in determining the phenotypic severity.
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Affiliation(s)
- Kosuke Izumi
- Division of Medical Genetics, Nagano Children's Hospital, Azumino, Japan.,Research Center for Epigenetic Disease, Institute for Molecular and Cellular Biosciences, the University of Tokyo, Tokyo, Japan
| | - Daisuke Hayashi
- Division of Medical Genetics, Nagano Children's Hospital, Azumino, Japan
| | - Christopher M Grochowski
- Department of Pathology and Laboratory Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Noriko Kubota
- Department of Laboratory Medicine, Nagano Children's Hospital, Azumino, Japan.,Life Science Research Center, Nagano Children's Hospital, Azumino, Japan
| | - Eriko Nishi
- Division of Medical Genetics, Nagano Children's Hospital, Azumino, Japan.,Life Science Research Center, Nagano Children's Hospital, Azumino, Japan.,Department of Medical Genetics, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Michiko Arakawa
- Division of Medical Genetics, Nagano Children's Hospital, Azumino, Japan
| | - Takehiko Hiroma
- Division of Neonatology, Nagano Children's Hospital, Azumino, Japan
| | - Tomoko Hatata
- Department of Pediatric Surgery, Nagano Children's Hospital, Azumino, Japan
| | - Yoshifumi Ogiso
- Division of Clinical Pathology, Nagano Children's Hospital, Azumino, Japan
| | - Tomohiko Nakamura
- Life Science Research Center, Nagano Children's Hospital, Azumino, Japan.,Division of Neonatology, Nagano Children's Hospital, Azumino, Japan
| | - Alexandra M Falsey
- Department of Pathology and Laboratory Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Eiko Hidaka
- Department of Laboratory Medicine, Nagano Children's Hospital, Azumino, Japan.,Life Science Research Center, Nagano Children's Hospital, Azumino, Japan
| | - Nancy B Spinner
- Department of Pathology and Laboratory Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Cooper DN, Krawczak M, Polychronakos C, Tyler-Smith C, Kehrer-Sawatzki H. Where genotype is not predictive of phenotype: towards an understanding of the molecular basis of reduced penetrance in human inherited disease. Hum Genet 2013; 132:1077-130. [PMID: 23820649 PMCID: PMC3778950 DOI: 10.1007/s00439-013-1331-2] [Citation(s) in RCA: 417] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/15/2013] [Indexed: 02/06/2023]
Abstract
Some individuals with a particular disease-causing mutation or genotype fail to express most if not all features of the disease in question, a phenomenon that is known as 'reduced (or incomplete) penetrance'. Reduced penetrance is not uncommon; indeed, there are many known examples of 'disease-causing mutations' that fail to cause disease in at least a proportion of the individuals who carry them. Reduced penetrance may therefore explain not only why genetic diseases are occasionally transmitted through unaffected parents, but also why healthy individuals can harbour quite large numbers of potentially disadvantageous variants in their genomes without suffering any obvious ill effects. Reduced penetrance can be a function of the specific mutation(s) involved or of allele dosage. It may also result from differential allelic expression, copy number variation or the modulating influence of additional genetic variants in cis or in trans. The penetrance of some pathogenic genotypes is known to be age- and/or sex-dependent. Variable penetrance may also reflect the action of unlinked modifier genes, epigenetic changes or environmental factors. At least in some cases, complete penetrance appears to require the presence of one or more genetic variants at other loci. In this review, we summarize the evidence for reduced penetrance being a widespread phenomenon in human genetics and explore some of the molecular mechanisms that may help to explain this enigmatic characteristic of human inherited disease.
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Affiliation(s)
- David N. Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN UK
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Christian-Albrechts University, 24105 Kiel, Germany
| | | | - Chris Tyler-Smith
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
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Abstract
Tuberous sclerosis complex (TSC) is a genetic disorder characterized by mammalian target of rapamycin (mTOR) activation and growth of benign tumors. Some TSC lesions, such as cardiac rhabdomyomas and cortical tubers in the brain, occur in fetuses, and some, such as renal angiomyolipomas (AMLs) and skin angiofibromas, develop over years. Recently, the mTOR inhibitor everolimus was shown to be effective in the treatment of subependymal giant cell astrocytomas (a brain tumor) and renal AMLs (kidney tumors) in TSC patients. We present monozygotic twin sisters affected with TSC. Since age 4 years, 1 of the sisters has been treated with everolimus; the other sister received no mTOR inhibitor treatment. After 24-month follow-up, everolimus treatment resulted in a significant brain tumor volume decrease in the treated twin. This child presents no facial angiofibroma, and no renal AMLs. The brain tumor in the nontreated sister is stable in size, but in the meantime, she has developed significant facial angiofibroma and renal AMLs. This observation indicates that early mTOR inhibition in TSC patients may prevent the development of TSC lesions and alter the natural history of the disease.
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Affiliation(s)
- Katarzyna Kotulska
- Department of Science, The Children's Memorial Health Institute, Warsaw, Poland.
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Zwijnenburg PJG, Meijers-Heijboer H, Boomsma DI. Identical but not the same: the value of discordant monozygotic twins in genetic research. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:1134-49. [PMID: 20468073 DOI: 10.1002/ajmg.b.31091] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Monozygotic (MZ) twins show remarkable resemblance in many aspects of behavior, health, and disease. Until recently, MZ twins were usually called "genetically identical"; however, evidence for genetic and epigenetic differences within rare MZ twin pairs has accumulated. Here, we summarize the literature on MZ twins discordant for Mendelian inherited disorders and chromosomal abnormalities. A systematic literature search for English articles on discordant MZ twin pairs was performed in Web of Science and PubMed. A total number of 2,016 publications were retrieved and reviewed and 439 reports were retained. Discordant MZ twin pairs are informative in respect to variability of phenotypic expression, pathogenetic mechanisms, epigenetics, and post-zygotic mutagenesis and may serve as a model for research on genetic defects. The analysis of single discordant MZ twin pairs may represent an elegant approach to identify genes in inherited disorders.
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Affiliation(s)
- Petra J G Zwijnenburg
- Department of Clinical Genetics, VU University Medical Center, de Boelelaan 1117, Amsterdam, the Netherlands.
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Jansen AC, Sancak O, D'Agostino MD, Badhwar A, Roberts P, Gobbi G, Wilkinson R, Melanson D, Tampieri D, Koenekoop R, Gans M, Maat-Kievit A, Goedbloed M, van den Ouweland AMW, Nellist M, Pandolfo M, McQueen M, Sims K, Thiele EA, Dubeau F, Andermann F, Kwiatkowski DJ, Halley DJJ, Andermann E. Unusually mild tuberous sclerosis phenotype is associated with TSC2 R905Q mutation. Ann Neurol 2006; 60:528-539. [PMID: 17120248 DOI: 10.1002/ana.21037] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To report the clinical manifestations and functional aspects of Tuberous Sclerosis Complex (TSC), resulting from Codon 905 mutations in TSC2 gene. METHODS We performed a detailed study of the TSC phenotype and genotype in a large French-Canadian kindred (Family A). Subsequently, clinical and molecular data on 18 additional TSC families with missense mutations at the same codon of TSC2 were collected. Functional studies were performed on the different missense changes and related to the phenotype. RESULTS A 2714G>A (R905Q) mutation was identified in Family A. The TSC phenotype in this family was unusually mild and characterized by hypomelanotic macules or focal seizures that remitted spontaneously or were easily controlled with medication. Diagnostic criteria were met in only a minority of mutation carriers. Other families with the R905Q mutation were found to have a similar mild phenotype. In contrast, patients with a 2713C>T (R905W) or a 2713C>G (R905G) mutation had more severe phenotypes. Although all three amino acid substitutions were pathogenic, the R905W and R905G substitutions affected tuberin function more severely than R905Q. INTERPRETATION Codon 905 missense mutations in TSC2 are relatively common. The TSC2 R905Q mutation is associated with unusually mild disease, consistent with functional studies. Combined with previous reports, it is apparent that certain TSC2 missense mutations are associated with a mild form of tuberous sclerosis, which in many patients does not meet standard diagnostic criteria. These findings have implications for the large number of patients with limited clinical features of TSC and for genetic counseling in these families.
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Affiliation(s)
- An C Jansen
- Neurogenetics Unit, Montreal Neurological Hospital and Institute, McGill University, Montreal, Quebec, Canada
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Choi JE, Chae JH, Hwang YS, Kim KJ. Mutational analysis of TSC1 and TSC2 in Korean patients with tuberous sclerosis complex. Brain Dev 2006; 28:440-6. [PMID: 16554133 DOI: 10.1016/j.braindev.2006.01.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 01/19/2006] [Accepted: 01/22/2006] [Indexed: 11/27/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a broad phenotypic spectrum that includes seizures, mental retardation, renal dysfunction and dermatological abnormalities. TSC is caused by mutations affecting either of the tumor-suppressor genes TSC1 and TSC2. At least 495 mutations of TSC1 and TSC2 have been reported. Twenty-two males and 22 females who were diagnosed with TSC at the Seoul National University Children's Hospital between 1982 and 2002 were enrolled in the study. Forty-four patients were from different families and included nine familial cases and 35 sporadic cases. Denaturing high performance liquid chromatography and DNA sequencing analysis of TSC1 and TSC2 revealed 13 types of mutations (30%). One novel mutation of TSC1 and nine novel mutations of TSC2 were identified. The TSC1 mutation and one of the nine TSC2 mutations were missense mutations and seven of the nine TSC2 mutations caused truncation of proteins. One novel single nucleotide substitution was identified at the consensus splicing donor site of exon 39 (c.5,069-1G>A). This mutation is predicted to cause a splicing error. Of the TSC2 mutation loci, the correlation with cardiac rhabdomyoma was more significant when the mutation was in the C-terminal part of tuberin than the N-terminal part. This is the first extensive mutational analysis of TSC1 and TSC2 in Korean TSC patients.
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Affiliation(s)
- Ji-Eun Choi
- Department of Pediatrics, Borame Hospital affiliated to Seoul National University Hospital, 395 shindaebang-2-dong, Dongjak-gu, 156-707 Seoul, South Korea.
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