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1.
BMJ Case Rep ; 12(9)2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31519716

RESUMO

Tay-Sachs disease (TSD) is a type 1 gangliosidosis (GM2) and caused by hexosaminidase A deficiency resulting in abnormal sphingolipid metabolism and deposition of precursors in different organs. It is a progressive neurodegenerative disorder transmitted in an autosomal-recessive manner. There is an accumulation of GM2 in neurocytes and retinal ganglions which result in progressive loss of neurological function and formation of the cherry-red spot which is the hallmark of TSD. We report the first case of juvenile TSD from Pakistan in a child with death of an older sibling without the diagnosis.


Assuntos
Doença de Tay-Sachs/diagnóstico , Doença de Tay-Sachs/genética , Cadeia alfa da beta-Hexosaminidase/genética , Pré-Escolar , Transtornos Neurológicos da Marcha/diagnóstico , Transtornos Neurológicos da Marcha/etiologia , Humanos , Masculino , Mutação/genética , Paquistão/epidemiologia , Cuidados Paliativos/métodos , Doença de Tay-Sachs/fisiopatologia , Sequenciamento Completo do Exoma/métodos
2.
J Hum Genet ; 64(10): 985-994, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31388111

RESUMO

Tay-Sachs disease (TSD) (OMIM) is a neurodegenerative lysosomal storage disorder caused due to mutations in the HEXA gene. To date, nearly 190 mutations have been reported in HEXA gene. Here, we have characterized 34 enzymatically confirmed TSD families to investigate the presence of novel as well as known variants in HEXA gene. Overall study detected 25 variants belonging to 31 affected TSD patients and 3 carrier couples confirmed by enzyme study. Of these 17 patients harbors 15 novel variants, including seven missense variants [p.V206L, p.Y213H, p.R252C, p.F257S, p.C328G, p.G454R, and p.P475R], four nonsense variant [p.S9X, p.E91X, p.W420X, and p.W482X], two splice site variants [c.347-1G>A and c.460-1G>A], and two small deletion [c.1349delC (p.A450VfsX3) and c.52delG (p.G18Dfs*82)]. While remaining 17 patients harbors 10 previously reported variants that includes six missense variants [p.M1T, p.R170Q, p.D322Y, p.D322N, p.E462V, and p.R499C], one nonsense variant [p.Q106X], two splice site variants [c.1073+1G>A and c.459+4A>G] and one 4 bp insertion [c.1278insTATC (p.Y427IfsX5)]. In conclusion, Indian infantile TSD patients provide newer insight into the molecular heterogeneity of the TSD. Combining present study and our earlier studies, we have observed that 67% genotypes found in Indian TSD patients are novel, which are associated with severe infantile phenotypes, while rest 33% genotypes found in our cohort were previously reported in various populations. In addition, higher frequency of the p.E462V and c.1278insTATC mutations in the present study further support and suggest the prevalence of p.E462V mutation in the Indian population.


Assuntos
Doença de Tay-Sachs/genética , Cadeia alfa da beta-Hexosaminidase/genética , Alelos , Pré-Escolar , Códon sem Sentido , Demografia , Feminino , Estudos de Associação Genética , Humanos , Índia , Lactente , Masculino , Mutação de Sentido Incorreto , Deleção de Sequência , Doença de Tay-Sachs/enzimologia , Doença de Tay-Sachs/fisiopatologia , Cadeia alfa da beta-Hexosaminidase/química
3.
Methods Mol Biol ; 1885: 233-250, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30506202

RESUMO

Tay-Sachs disease (TSD) is an autosomal recessive lysosomal storage disorder caused by mutations of the HEXA gene resulting in the deficiency of hexosaminidase A (Hex A) and subsequent neuronal accumulation of GM2 gangliosides. Infantile TSD is a devastating and fetal neurodegenerative disease with death before the age of 3-5 years. A small proportion of TSD patients carry milder mutations and may present juvenile or adult onset milder disease. TSD is more prevalent among Ashkenazi Jewish (AJ) individuals and some other genetically isolated populations with carrier frequencies of approximately ~1:27 which is much higher than that of 1:300 in the general population. Carrier screening and prenatal testing for TSD are effective in preventing the birth of affected fetuses greatly diminishing the incidence of TSD. Testing of targeted HEXA mutations by genotyping or sequencing can detect 98% of carriers in AJ individuals; however, the detection rate is much lower for most other ethnic groups. When combined with enzyme analysis, above 98% of carriers can be reliably identified regardless of ethnic background. Multiplex PCR followed by allele-specific primer extension is one method to test for known and common mutations. Sanger sequencing or other sequencing methods are useful to identify private mutations. For prenatal testing, only predefined parental mutations need to be tested. In the event of unknown mutational status or the presence of variants of unknown significance (VUS), enzyme analysis must be performed in conjunction with DNA-based assays to enhance the diagnostic accuracy. Enzymatic assays involve the use of synthetic substrates 4-methylumbelliferyl-N-acetyl-ß-glucosamine (4-MUG) and 4-methylumbelliferyl-6-sulfo-2-acetamido-2-deoxy-ß-D-glucopyranoside (4-MUGS) to measure the percentage Hex A activity (Hex A%) and specific Hex A activity respectively. These biochemical and molecular tests can be performed in both direct specimens and cultured cells from chorionic villi sampling or amniocentesis.


Assuntos
Testes Genéticos , Diagnóstico Pré-Natal/métodos , Doença de Tay-Sachs/diagnóstico , Doença de Tay-Sachs/genética , Alelos , Contaminação por DNA , Análise Mutacional de DNA , Eletroforese Capilar , Testes Genéticos/métodos , Testes Genéticos/normas , Genótipo , Humanos , Mutação , Reação em Cadeia da Polimerase , Diagnóstico Pré-Natal/normas , Doença de Tay-Sachs/metabolismo , Cadeia alfa da beta-Hexosaminidase/genética , Cadeia alfa da beta-Hexosaminidase/metabolismo
4.
BMJ Case Rep ; 11(1)2018 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-30567231

RESUMO

Lysosomal storage disorders or lipidoses are a wide spectrum of inherited diseases caused by deficiency of a specific lysosomal hydrolase. About 134 mutations have been described so far and this number is gradually increasing with newer mutations being reported. We report a 28-month-old child who presented to us with neurodevelopment regression, seizures and cherry red spot in both eyes. His hexosaminidase A enzyme activity was reduced and genetic testing revealed a homozygous novel variation in HEXA (hexosaminidase A) gene in the DNA sample of the patient.


Assuntos
Hexosaminidase A/genética , Mutação , Doença de Tay-Sachs/genética , Pré-Escolar , Humanos , Índia , Masculino
5.
Orphanet J Rare Dis ; 13(1): 152, 2018 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-30220252

RESUMO

BACKGROUND: Tay-Sachs disease (TSD) is a rare neurodegenerative disorder caused by autosomal recessive mutations in the HEXA gene on chromosome 15 that encodes ß-hexosaminidase. Deficiency in HEXA results in accumulation of GM2 ganglioside, a glycosphingolipid, in lysosomes. Currently, there is no effective treatment for TSD. RESULTS: We generated induced pluripotent stem cells (iPSCs) from two TSD patient dermal fibroblast lines and further differentiated them into neural stem cells (NSCs). The TSD neural stem cells exhibited a disease phenotype of lysosomal lipid accumulation. The Tay-Sachs disease NSCs were then used to evaluate the therapeutic effects of enzyme replacement therapy (ERT) with recombinant human Hex A protein and two small molecular compounds: hydroxypropyl-ß-cyclodextrin (HPßCD) and δ-tocopherol. Using this disease model, we observed reduction of lipid accumulation by employing enzyme replacement therapy as well as by the use of HPßCD and δ-tocopherol. CONCLUSION: Our results demonstrate that the Tay-Sachs disease NSCs possess the characteristic phenotype to serve as a cell-based disease model for study of the disease pathogenesis and evaluation of drug efficacy. The enzyme replacement therapy with recombinant Hex A protein and two small molecules (cyclodextrin and tocopherol) significantly ameliorated lipid accumulation in the Tay-Sachs disease cell model.


Assuntos
Células-Tronco Neurais/citologia , Doença de Tay-Sachs/tratamento farmacológico , Doença de Tay-Sachs/terapia , 2-Hidroxipropil-beta-Ciclodextrina/uso terapêutico , Diferenciação Celular/fisiologia , Linhagem Celular , Terapia de Reposição de Enzimas/métodos , Feminino , Imunofluorescência , Gangliosidoses GM2/metabolismo , Hexosaminidase A/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/fisiologia , Masculino , Repetições de Microssatélites/genética , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/fisiologia , Pichia/metabolismo , Espectrometria de Massas em Tandem , Doença de Tay-Sachs/genética , Doença de Tay-Sachs/metabolismo , Tocoferóis/uso terapêutico
7.
BMC Med Genet ; 19(1): 109, 2018 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-29973161

RESUMO

BACKGROUND: Tay-Sachs disease (TSD) is a sphingolipid storage disorder caused by mutations in the HEXA gene. To date, nearly 170 mutations of HEXA have been described, including only one 7.6 kb large deletion. METHODS: Multiplex Ligation-dependent Probe Amplification (MLPA) study was carried out in 5 unrelated patients for copy number changes where heterozygous and/or homozygous disease causing mutation/s could not be identified in the coding region by sequencing of HEXA gene. RESULTS: The study has identified the presence of a homozygous deletion of exon-2 and exon-3 in two patients, two patient showed compound heterozygosity with exon 1 deletion combined with missense mutation p.E462V and one patient was identified with duplication of exon-1 with novel variants c.1527-2A > T as a second allele. CONCLUSION: This is the first report of deletion/duplication in HEXA gene providing a new insight into the molecular basis of TSD and use of MLPA assay for detecting large copy number changes in the HEXA gene.


Assuntos
Deleção de Sequência/genética , Doença de Tay-Sachs/genética , Cadeia alfa da beta-Hexosaminidase/genética , Éxons/genética , Feminino , Heterozigoto , Homozigoto , Humanos , Índia , Lactente , Masculino , Mutação de Sentido Incorreto/genética
8.
Curr Gene Ther ; 18(2): 68-89, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29618308

RESUMO

Tay-Sachs disease, caused by impaired ß-N-acetylhexosaminidase activity, was the first GM2 gangliosidosis to be studied and one of the most severe and earliest lysosomal diseases to be described. The condition, associated with the pathological build-up of GM2 ganglioside, has acquired almost iconic status and serves as a paradigm in the study of lysosomal storage diseases. Inherited as a classical autosomal recessive disorder, this global disease of the nervous system induces developmental arrest with regression of attained milestones; neurodegeneration progresses rapidly to cause premature death in young children. There is no effective treatment beyond palliative care, and while the genetic basis of GM2 gangliosidosis is well established, the molecular and cellular events, from diseasecausing mutations and glycosphingolipid storage to disease manifestations, remain to be fully delineated. Several therapeutic approaches have been attempted in patients, including enzymatic augmentation, bone marrow transplantation, enzyme enhancement, and substrate reduction therapy. Hitherto, none of these stratagems has materially altered the course of the disease. Authentic animal models of GM2 gangliodidosis have facilitated in-depth evaluation of innovative applications such as gene transfer, which in contrast to other interventions, shows great promise. This review outlines current knowledge pertaining the pathobiology as well as potential innovative treatments for the GM2 gangliosidoses.


Assuntos
Transplante de Medula Óssea , Terapia de Reposição de Enzimas , Terapia Genética , Doença de Sandhoff/genética , Doença de Sandhoff/terapia , Doença de Tay-Sachs/genética , Doença de Tay-Sachs/terapia , Animais , Modelos Animais de Doenças , Glicoesfingolipídeos/metabolismo , Humanos , Lactente , Lisossomos/enzimologia , Lisossomos/genética , Lisossomos/patologia , Camundongos , Mutação , Doenças Raras , Doença de Sandhoff/enzimologia , Doença de Sandhoff/patologia , Doença de Tay-Sachs/enzimologia , Doença de Tay-Sachs/patologia , beta-N-Acetil-Hexosaminidases/genética
9.
Cochrane Database Syst Rev ; 3: CD010849, 2018 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-29537064

RESUMO

BACKGROUND: Globally, about five per cent of children are born with congenital or genetic disorders. The most common autosomal recessive conditions are thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease, with higher carrier rates in specific patient populations. Identifying and counselling couples at genetic risk of the conditions before pregnancy enables them to make fully informed reproductive decisions, with some of these choices not being available if genetic counselling is only offered in an antenatal setting. This is an update of a previously published review. OBJECTIVES: To assess the effectiveness of systematic preconception genetic risk assessment to improve reproductive outcomes in women and their partners who are identified as carriers of thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease in healthcare settings when compared to usual care. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Trials Registers. In addition, we searched for all relevant trials from 1970 (or the date at which the database was first available if after 1970) to date using electronic databases (MEDLINE, Embase, CINAHL, PsycINFO), clinical trial databases (National Institutes of Health, Clinical Trials Search portal of the World Health Organization, metaRegister of controlled clinical trials), and hand searching of key journals and conference abstract books from 1998 to date (European Journal of Human Genetics, Genetics in Medicine, Journal of Community Genetics). We also searched the reference lists of relevant articles, reviews and guidelines and also contacted subject experts in the field to request any unpublished or other published trials.Date of latest search of the registers: 20 June 2017.Date of latest search of all other sources: 16 November 2017. SELECTION CRITERIA: Any randomised or quasi-randomised controlled trials (published or unpublished) comparing reproductive outcomes of systematic preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease when compared to usual care. DATA COLLECTION AND ANALYSIS: We identified 25 papers, describing 16 unique trials which were potentially eligible for inclusion in the review. However, after assessment, no randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease were found. MAIN RESULTS: No randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis and Tay-Sachs disease were included. One ongoing trial has been identified which may potentially eligible for inclusion once completed. AUTHORS' CONCLUSIONS: As no randomised controlled trials of preconception genetic risk assessment for thalassaemia, sickle cell disease, cystic fibrosis, or Tay-Sachs disease were found for inclusion in this review, the research evidence for current policy recommendations is limited to non-randomised studies.Information from well-designed, adequately powered, randomised trials is desirable in order to make more robust recommendations for practice. However, such trials must also consider the legal, ethical, and cultural barriers to implementation of preconception genetic risk assessment.


Assuntos
Anemia Falciforme/genética , Fibrose Cística/genética , Triagem de Portadores Genéticos , Cuidado Pré-Concepcional , Doença de Tay-Sachs/genética , Talassemia/genética , Feminino , Humanos , Medição de Risco
11.
Exp Neurol ; 299(Pt A): 26-41, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28974375

RESUMO

Tay-Sachs disease is a severe lysosomal storage disorder caused by mutations in Hexa, the gene that encodes for the α subunit of lysosomal ß-hexosaminidase A (HEXA), which converts GM2 to GM3 ganglioside. Unexpectedly, Hexa-/- mice have a normal lifespan and show no obvious neurological impairment until at least one year of age. These mice catabolize stored GM2 ganglioside using sialidase(s) to remove sialic acid and form the glycolipid GA2, which is further processed by ß-hexosaminidase B. Therefore, the presence of the sialidase (s) allows the consequences of the Hexa defect to be bypassed. To determine if the sialidase NEU3 contributes to GM2 ganglioside degradation, we generated a mouse model with combined deficiencies of HEXA and NEU3. The Hexa-/-Neu3-/- mice were healthy at birth, but died at 1.5 to 4.5months of age. Thin-layer chromatography and mass spectrometric analysis of the brains of Hexa-/-Neu3-/- mice revealed the abnormal accumulation of GM2 ganglioside. Histological and immunohistochemical analysis demonstrated cytoplasmic vacuolation in the neurons. Electron microscopic examination of the brain, kidneys and testes revealed pleomorphic inclusions of many small vesicles and complex lamellar structures. The Hexa-/-Neu3-/- mice exhibited progressive neurodegeneration with neuronal loss, Purkinje cell depletion, and astrogliosis. Slow movement, ataxia, and tremors were the prominent neurological abnormalities observed in these mice. Furthermore, radiographs revealed abnormalities in the skeletal bones of the Hexa-/-Neu3-/- mice. Thus, the Hexa-/-Neu3-/- mice mimic the neuropathological and clinical abnormalities of the classical early-onset Tay-Sachs patients, and provide a suitable model for the future pre-clinical testing of potential treatments for this condition.


Assuntos
Gangliosidoses GM2/genética , Hexosaminidase B/genética , Neuraminidase/genética , Doença de Tay-Sachs/genética , Animais , Química Encefálica/genética , Vesículas Citoplasmáticas/patologia , Gangliosidoses GM2/metabolismo , Gliose/genética , Gliose/patologia , Glicoesfingolipídeos/metabolismo , Coxeadura Animal/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neuraminidase/deficiência , Neurônios/patologia , Células de Purkinje/patologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Doença de Tay-Sachs/patologia
12.
Hum Gene Ther ; 29(3): 312-326, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28922945

RESUMO

Tay-Sachs disease (TSD) is a fatal neurodegenerative disorder caused by a deficiency of the enzyme hexosaminidase A (HexA). TSD also occurs in sheep, the only experimental model of TSD that has clinical signs of disease. The natural history of sheep TSD was characterized using serial neurological evaluations, 7 Tesla magnetic resonance imaging, echocardiograms, electrodiagnostics, and cerebrospinal fluid biomarkers. Intracranial gene therapy was also tested using AAVrh8 monocistronic vectors encoding the α-subunit of Hex (TSD α) or a mixture of two vectors encoding both the α and ß subunits separately (TSD α + ß) injected at high (1.3 × 1013 vector genomes) or low (4.2 × 1012 vector genomes) dose. Delay of symptom onset and/or reduction of acquired symptoms were noted in all adeno-associated virus-treated sheep. Postmortem evaluation showed superior HexA and vector genome distribution in the brain of TSD α + ß sheep compared to TSD α sheep, but spinal cord distribution was low in all groups. Isozyme analysis showed superior HexA formation after treatment with both vectors (TSD α + ß), and ganglioside clearance was most widespread in the TSD α + ß high-dose sheep. Microglial activation and proliferation in TSD sheep-most prominent in the cerebrum-were attenuated after gene therapy. This report demonstrates therapeutic efficacy for TSD in the sheep brain, which is on the same order of magnitude as a child's brain.


Assuntos
Dependovirus , Terapia Genética , Doença de Tay-Sachs/terapia , Cadeia alfa da beta-Hexosaminidase/biossíntese , Cadeia beta da beta-Hexosaminidase/biossíntese , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/enzimologia , Modelos Animais de Doenças , Ecocardiografia , Humanos , Imagem por Ressonância Magnética , Microglia/enzimologia , Ovinos , Doença de Tay-Sachs/diagnóstico por imagem , Doença de Tay-Sachs/enzimologia , Doença de Tay-Sachs/genética , Cadeia alfa da beta-Hexosaminidase/genética , Cadeia beta da beta-Hexosaminidase/genética
13.
Int J Mol Sci ; 18(12)2017 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-29186855

RESUMO

Sphingolipids, long thought to be passive components of biological membranes with merely a structural role, have proved throughout the past decade to be major players in the pathogenesis of many human diseases. The study and characterization of several genetic disorders like Fabry's and Tay Sachs, where sphingolipid metabolism is disrupted, leading to a systemic array of clinical symptoms, have indeed helped elucidate and appreciate the importance of sphingolipids and their metabolites as active signaling molecules. In addition to being involved in dynamic cellular processes like apoptosis, senescence and differentiation, sphingolipids are implicated in critical physiological functions such as immune responses and pathophysiological conditions like inflammation and insulin resistance. Interestingly, the kidneys are among the most sensitive organ systems to sphingolipid alterations, rendering these molecules and the enzymes involved in their metabolism, promising therapeutic targets for numerous nephropathic complications that stand behind podocyte injury and renal failure.


Assuntos
Doença de Fabry/metabolismo , Nefropatias/metabolismo , Podócitos/metabolismo , Esfingolipídeos/metabolismo , Doença de Tay-Sachs/metabolismo , Animais , Doença de Fabry/genética , Doença de Fabry/terapia , Humanos , Nefropatias/genética , Nefropatias/terapia , Doença de Tay-Sachs/genética , Doença de Tay-Sachs/terapia , Pesquisa Médica Translacional
14.
Arch Med Res ; 48(3): 263-269, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28923328

RESUMO

BACKGROUND: The ascertainment of mutation frequencies in the general population may have impact on the population's wellbeing and respective healthcare services. Furthermore, it may help define which approaches will be more effective for certain patients based on the genetic cause of disease. AIM OF THE STUDY: Determine the frequency of three mutations, known to be a major cause of three distinct Lysosomal Storage Diseases (LSDs). METHODS: The following pre-requisites were met: each mutation accounted for over 55% of the disease alleles among previously reported unrelated patients, all three diseases were among the most prevalent LSDs in the population under study, they all involved devastating deterioration of the nervous system, lacked curative treatment and may be fatal in childhood or adolescence. The anonymous samples used in this study were representative of the whole population; mutations were tested by PCR based methods, positive results were further confirmed. The diseases studied were Mucopolysaccharidosis type I (Hurler, MIM 607014), Tay Sachs disease variant B1 (TS, MIM 272800) and Metachromatic Leukodystrophy (MLD, MIM 250100); the mutations were, respectively, p.W402X, p.R178C and c.465+1G>A. RESULTS AND CONCLUSION: Increased carrier frequencies were found for Tay Sachs disease variant B1 HEXA p.R178C mutation (1:340) and for the infantile MLD ARSA c.465+1G> A mutation (1:350) denoting higher risk for these sub-types of disease in Portugal and possibly in individuals of Iberian ancestry. Carrier screening in target populations may provide the foundations for more effective approaches to precision medicine.


Assuntos
Leucodistrofia Metacromática/genética , Mucopolissacaridose I/genética , Doença de Tay-Sachs/genética , Alelos , Humanos , Recém-Nascido , Mutação , Taxa de Mutação , Portugal
15.
J Christ Nurs ; 34(4): 246-249, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28902054

RESUMO

Several genetic disorders are specific to Jewish heritage; one of the most devastating is Tay-Sachs disease.Tay-Sachs is a fatal hereditary disease, causing progressive neurological problems for which there is no cure. Ethical issues surrounding genetic testing for Tay-Sachs within the Jewish community continue to be complex and multifaceted. A perspective of Tay-Sachs, using rights-based ethics and virtue ethics as a theoretical framework, is explored.


Assuntos
Triagem de Portadores Genéticos/ética , Testes Genéticos/ética , Judeus/genética , Judaísmo , Doença de Tay-Sachs/diagnóstico , Doença de Tay-Sachs/etnologia , Humanos , Doença de Tay-Sachs/genética , Estados Unidos
16.
Anal Chem ; 89(4): 2622-2627, 2017 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-28194950

RESUMO

Single nucleotide polymorphisms (SNPs) are the most fundamental internal causes for many genetic diseases. However, the location information on SNPs in a specific DNA sequence is not well acquired through current SNPs detection methods, except for accurate DNA sequencing. Here we report a fluorescence enhancement phenomenon in the process of two silver nanoclusters (AgNCs) approaching closely to form a nanocluster dimer (NCD). The fluorescence intensity is sensitive to the distance between two AgNCs; therefore, the NCD lights into different fluorescence intensities upon binding SNPs targets with mismatched bases at different positions. Interestingly, the fluorescence intensities of the NCD decrease linearly when the position of single mismatched base moves gradually from the middle point to the end of the target DNA. The NCD is a single probe acting as a universal platform to pinpoint various SNP positions. With this single probe, we cannot only identify the existence of SNPs but also pinpoint the location of a specific single mismatched base in the adjacent positions. This strategy is feasible to detect specific gene point mutations in clinical samples.


Assuntos
Nanopartículas Metálicas/química , Polimorfismo de Nucleotídeo Único , Espectrometria de Fluorescência , Pareamento Incorreto de Bases , DNA/sangue , DNA/metabolismo , Sondas de DNA/metabolismo , Dimerização , Corantes Fluorescentes/química , Humanos , Cinética , Prata/química , Doença de Tay-Sachs/genética , Doença de Tay-Sachs/patologia
17.
Obstet Gynecol ; 129(3): e41-e55, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28225426

RESUMO

Carrier screening is a term used to describe genetic testing that is performed on an individual who does not have any overt phenotype for a genetic disorder but may have one variant allele within a gene(s) associated with a diagnosis. Information about carrier screening should be provided to every pregnant woman. Carrier screening and counseling ideally should be performed before pregnancy because this enables couples to learn about their reproductive risk and consider the most complete range of reproductive options. A patient may decline any or all screening. When an individual is found to be a carrier for a genetic condition, his or her relatives are at risk of carrying the same mutation. The patient should be encouraged to inform his or her relatives of the risk and the availability of carrier screening. If an individual is found to be a carrier for a specific condition, the patient's reproductive partner should be offered testing in order to receive informed genetic counseling about potential reproductive outcomes. If both partners are found to be carriers of a genetic condition, genetic counseling should be offered. What follows is a detailed discussion of some of the more common genetic conditions for which carrier screening is recommended in at least some segments of the population.


Assuntos
Triagem de Portadores Genéticos , Aconselhamento Genético , Testes Genéticos/normas , Judeus/genética , Fibrose Cística/genética , Revelação , Europa Oriental/etnologia , Feminino , Síndrome do Cromossomo X Frágil/genética , Hemoglobinopatias/genética , Humanos , Aceitação pelo Paciente de Cuidados de Saúde , Educação de Pacientes como Assunto , Gravidez , Medição de Risco , Doença de Tay-Sachs/genética
19.
Stem Cell Res ; 17(2): 289-291, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27879213

RESUMO

Human iPSC line TSD-01-hiPSC was generated from fibroblasts of a patient with infantile Tay-Sachs disease (TSD). The patient is compound heterozygous at the HEXA gene by carrying a 1278insTATC allele and an IVS12+1G>C allele. STEMCCA lentivirus, which expresses OCT4, SOX2, KLF4, and c-MYC from a polycistronic transcript, were used for reprogramming. TSD-01-hiPSC express pluripotency markers such as OCT4, SOX2, NANOG, Tra-1-60, and alkaline phosphatase, and can differentiate into tissues from all the three embryonic germ layers. This TSD patient-derived hiPSC line may serve as a valuable in vitro tool for disease modeling and drug test.


Assuntos
Reprogramação Celular , Células-Tronco Pluripotentes Induzidas/citologia , Doença de Tay-Sachs/patologia , Cadeia alfa da beta-Hexosaminidase/genética , Alelos , Animais , Sequência de Bases , Diferenciação Celular , Linhagem Celular , Análise Mutacional de DNA , Fibroblastos/citologia , Fibroblastos/metabolismo , Genótipo , Heterozigoto , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/transplante , Cariótipo , Masculino , Camundongos , Camundongos Endogâmicos NOD , Mutagênese Insercional , Doença de Tay-Sachs/genética , Doença de Tay-Sachs/metabolismo , Teratoma/patologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transplante Heterólogo
20.
Mol Biol Cell ; 27(24): 3813-3827, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27682588

RESUMO

Loss of function of the enzyme ß-hexosaminidase A (HexA) causes the lysosomal storage disorder Tay-Sachs disease (TSD). It has been proposed that mutations in the α chain of HexA can impair folding, enzyme assembly, and/or trafficking, yet there is surprisingly little known about the mechanisms of these potential routes of pathogenesis. We therefore investigated the biosynthesis and trafficking of TSD-associated HexA α mutants, seeking to identify relevant cellular quality control mechanisms. The α mutants E482K and G269S are defective in enzymatic activity, unprocessed by lysosomal proteases, and exhibit altered folding pathways compared with wild-type α. E482K is more severely misfolded than G269S, as observed by its aggregation and inability to associate with the HexA ß chain. Importantly, both mutants are retrotranslocated from the endoplasmic reticulum (ER) to the cytosol and are degraded by the proteasome, indicating that they are cleared via ER-associated degradation (ERAD). Leveraging these discoveries, we observed that manipulating the cellular folding environment or ERAD pathways can alter the kinetics of mutant α degradation. Additionally, growth of patient fibroblasts at a permissive temperature or with chemical chaperones increases cellular Hex activity by improving mutant α folding. Therefore modulation of the ER quality control systems may be a potential therapeutic route for improving some forms of TSD.


Assuntos
Hexosaminidase A/genética , Hexosaminidase A/metabolismo , Retículo Endoplasmático/metabolismo , Degradação Associada com o Retículo Endoplasmático/fisiologia , Células HEK293 , Hexosaminidase A/biossíntese , Hexosaminidase A/fisiologia , Humanos , Lisossomos/metabolismo , Chaperonas Moleculares/metabolismo , Mutação , Cultura Primária de Células , Transporte Proteico/fisiologia , Proteólise , Doença de Tay-Sachs/genética , Doença de Tay-Sachs/metabolismo , beta-N-Acetil-Hexosaminidases/metabolismo
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