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1.
J Cardiovasc Dev Dis ; 10(9)2023 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-37754822

RESUMEN

Rare familial spontaneous coronary artery dissection (SCAD) kindreds implicate genetic disease predisposition and provide a unique opportunity for candidate gene discovery. Whole-genome sequencing was performed in fifteen probands with non-syndromic SCAD who had a relative with SCAD, eight of whom had a second relative with extra-coronary arteriopathy. Co-segregating variants and associated genes were prioritized by quantitative variant, gene, and disease-level metrics. Curated public databases were queried for functional relationships among encoded proteins. Fifty-four heterozygous coding variants in thirteen families co-segregated with disease and fulfilled primary filters of rarity, gene variation constraint, and predicted-deleterious protein effect. Secondary filters yielded 11 prioritized candidate genes in 12 families, with high arterial tissue expression (n = 7), high-confidence protein-level interactions with genes associated with SCAD previously (n = 10), and/or previous associations with connective tissue disorders and aortopathies (n = 3) or other vascular phenotypes in mice or humans (n = 11). High-confidence associations were identified among 10 familial SCAD candidate-gene-encoded proteins. A collagen-encoding gene was identified in five families, two with distinct variants in COL4A2. Familial SCAD is genetically heterogeneous, yet perturbations of extracellular matrix, cytoskeletal, and cell-cell adhesion proteins implicate common disease-susceptibility pathways. Incomplete penetrance and variable expression suggest genetic or environmental modifiers.

2.
Int J Mol Sci ; 24(8)2023 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-37108800

RESUMEN

Mutations in APOB are the second most frequent cause of familial hypercholesterolemia (FH). APOB is highly polymorphic, and many variants are benign or of uncertain significance, so functional analysis is necessary to ascertain their pathogenicity. Our aim was to identify and characterize APOB variants in patients with hypercholesterolemia. Index patients (n = 825) with clinically suspected FH were analyzed using next-generation sequencing. In total, 40% of the patients presented a variant in LDLR, APOB, PCSK9 or LDLRAP1, with 12% of the variants in APOB. These variants showed frequencies in the general population lower than 0.5% and were classified as damaging and/or probably damaging by 3 or more predictors of pathogenicity. The variants c.10030A>G;p.(Lys3344Glu) and c.11401T>A;p.(Ser3801Thr) were characterized. The p.(Lys3344Glu) variant co-segregated with high low-density lipoprotein (LDL)-cholesterol in 2 families studied. LDL isolated from apoB p.(Lys3344Glu) heterozygous patients showed reduced ability to compete with fluorescently-labelled LDL for cellular binding and uptake compared with control LDL and was markedly deficient in supporting U937 cell proliferation. LDL that was carrying apoB p.(Ser3801Thr) was not defective in competing with control LDL for cellular binding and uptake. We conclude that the apoB p.(Lys3344Glu) variant is defective in the interaction with the LDL receptor and is causative of FH, whereas the apoB p.(Ser3801Thr) variant is benign.


Asunto(s)
Hiperlipoproteinemia Tipo II , Proproteína Convertasa 9 , Humanos , Proproteína Convertasa 9/genética , Apolipoproteínas B/genética , LDL-Colesterol/genética , Células U937 , Hiperlipoproteinemia Tipo II/genética
3.
Virology ; 578: 1-6, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36423573

RESUMEN

PB1 influenza virus retain traces of interspecies transmission and adaptation. Previous phylogenetic analyses highlighted mutations L298I, R386K and I517V in PB1 to have putatively ameliorated the A(H1N1)pdm09 adaptation to the human host. This study aimed to evaluate the reversal of these mutations and infer the role of these residues in the virus overall fitness and adaptation. We generate PB1-mutated viruses introducing I298L, K386R and V517I mutations in PB1 and evaluate their phenotypic impact on viral growth and on antigen yield. We observed a decrease in viral growth accompanied by a reduction in hemagglutination titer and neuraminidase activity, in comparison with wt. Our data indicate that the adaptive evolution occurred in the PB1 leads to an improved overall viral fitness; and such biologic advantaged has the potential to be applied to the optimization of influenza vaccine seed prototypes.


Asunto(s)
Subtipo H1N1 del Virus de la Influenza A , Virus de la Influenza A , Vacunas contra la Influenza , Gripe Humana , Humanos , Subtipo H1N1 del Virus de la Influenza A/genética , Filogenia , Proteínas Virales/genética , Virus de la Influenza A/genética , Vacunas contra la Influenza/genética
4.
Front Oncol ; 12: 963364, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36387164

RESUMEN

Background: Li-Fraumeni syndrome (LFS) and Li-Fraumeni-like (LFL) syndrome are rare hereditary diseases characterized by predisposition to a diverse spectrum of cancer types, primarily sarcoma. The pathogenic variants underlying the majority of LFL cases remain to be explored. Methods: We performed whole-exome sequencing (WES) on 13 core members of a large LFL family with highly aggregated incidences of cancers, including cases with sarcoma, non-small cell lung cancer and cardiac angiosarcoma, and conducted a comprehensive literature review of candidate gene associations in LFS/LFL syndromes or sarcoma to identify potential pathogenic germline variants. Results: No germline variants in the best-known LFL/LFS-associated gene TP53 were detected. Of all the genes associated with LFS/LFL or sarcoma that we have surveyed, we identified a novel p.P35L germline variant in POT1 (protection of telomeres 1). Germline and somatic alterations in POT1 have been implicated in a series of familial cancers, including angiosarcoma, glioma, melanoma and colorectal cancer. This particular variant is located in the telomere-binding OB1 domain, which is important in maintaining the proper telomere length, and showed high conservation across different POT1 orthologues. No record of the variant was found in any of the 1000 genomes, ExAC, gnomAD, dpSNP and COSMIC databases. Prediction algorithms and in silico structural analysis suggested completely disrupted protein structure and function of POT1 in the presence of this mutation. Conclusions: Leveraging WES, we identified a novel germline risk allele, p.P35L in POT1, that likely predisposes to LFL syndrome. Our results support the routine testing of POT1 and other LFL/LFS-associated genes in the risk populations to enable early cancer diagnosis, prevention and intervention.

5.
Indian J Psychol Med ; 44(4): 366-370, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35949625

RESUMEN

Background: Cognitive impairment is the core outcome defining feature in schizophrenia. Schizophrenia, in the context of a broader neurodegenerative conceptualization, may have shared etiology with major neurocognitive disorders (MNCD). To elucidate this association there is definite need to explore the familial loading of dementia, in families of patients with schizophrenia. Methods: The authors compared relatives including parental generation and siblings of 100 cases (schizophrenia probands) and 100 controls (anxiety disorder) in order to assess the familial co-aggregation of MNCD. All cases and control were screened with Mini International Neuropsychiatric Interview screen for psychiatric morbidity. The pedigree analysis was conducted by family history method and Family Interview for Genetic Studies. Cognitive impairment in pedigree was screened by community screening instrument for dementia. Results: There was nonreporting of MNCD in the total 2538 relatives (proband siblings +parental generation) of both cases and controls. Diabetes mellitus was the most common somatic morbidity, found significantly more among the parental generation of cases than healthy controls (χ2 (1, 1713) = 6.452, P < 0.05). The odds of having various psychiatric and medical morbidities in the schizophrenia families compared to control are less than 1. Conclusion: There is no familial co-aggregation of MNCD in schizophrenia probands and common etiology between the two is less likely. Either schizophrenia could be counter-intuitively protective for MNCD or a reversible risk factor that can be prevented by effective treatments.

6.
Materials (Basel) ; 15(13)2022 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-35806522

RESUMEN

Since the successful separation of graphene from its bulk counterpart, two-dimensional (2D) layered materials have become the focus of research for their exceptional properties. The layered hexagonal boron nitride (h-BN), for instance, offers good lubricity, electrical insulation, corrosion resistance, and chemical stability. In recent years, the wide-band-gap layered h-BN has been recognized for its broad application prospects in neutron detection and quantum information processing. In addition, it has become very important in the field of 2D crystals and van der Waals heterostructures due to its versatility as a substrate, encapsulation layer, and a tunneling barrier layer for various device applications. However, due to the poor adhesion between h-BN and substrate and its high preparation temperature, it is very difficult to prepare large-area and denseh-BN films. Therefore, the controllable synthesis of h-BN films has been the focus of research in recent years. In this paper, the preparation methods and applications of h-BN films on III-V compounds are systematically summarized, and the prospects are discussed.

7.
Haemophilia ; 27(2): e204-e213, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33550700

RESUMEN

INTRODUCTION: von Willebrand factor (VWF) is a multimeric plasma glycoprotein that plays an important role in haemostasis. von Willebrand disease (VWD) is an inherited heterogeneous bleeding disorder caused by either a quantitative or qualitative defect of VWF. Type 3 VWD, the most severe form of the disease, leads to complete quantitative VWF deficiency. AIM: The present study aims to investigate the molecular pathogenesis of type 3 VWD patients from Southern Brazil. METHODS: The VWF gene was sequenced in 26 cases clinically diagnosed with type 3 VWD by next-generation sequencing using Ion Torrent PGM. RESULTS: In 25 patients, we were able to identify both disease-causing variants. We identified 72 different variants: 31 intronic and 41 exonic. Five novel variants were found: c.6976+5G>T; c.6885_6886insC; c.3378C>T (p.Cys1126); c.3346_3347insCCA; and c.2503G>T (p.Glu835*). Variants p.Pro2063Ser and p.Arg324* co-segregated in 17 patients, 15 of them in homozygosity. CONCLUSION: Our results may contribute to the discussion on whether the variant p.Pro2063Ser is pathogenic or not. Finally, the presence of a common haplotype in patients bearing these two variants suggests a founder effect for this variant in our region.


Asunto(s)
Enfermedad de von Willebrand Tipo 3 , Factor de von Willebrand , Sustitución de Aminoácidos , Brasil , Hemostasis , Humanos , Enfermedad de von Willebrand Tipo 3/genética , Enfermedades de von Willebrand/genética , Factor de von Willebrand/genética
8.
Hum Biol ; 93(3): 143-162, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-37733613

RESUMEN

Toll-like receptors (TLRs) are cellular innate immune receptors that explore microbial molecules. For instance, TLR4 can sense bacterial lipopolysaccharides, inducing cytokines and antimicrobial peptides against the bacteria. Single-nucleotide polymorphisms (SNPs) in TLR4 are associated with diseases such as septic shock. Therefore, investigations of common SNPs may help explain the pathogenesis of diseases and various innate immune responses to infections. This study investigated genotypic frequencies of the two common TLR4 SNPs, Asp299Gly and Thr399Ile, in a Kurdish population using restriction length fragment polymorphisms (RFLPs). Global frequencies of both TLR4 SNPs in different populations of sub-Saharan Africa, North Africa, western Asia, Eurasia, and East Asia were also used to infer human migrations and past settlements. The RFLP data demonstrate that, in the Kurdish population, the genotypic frequencies of both SNPs are similar to Iranian or other West Asian populations, which in turn are comparable to Eurasian populations, suggesting past admixture due to migrations, population intermixing, and common ancestry. Globally, the frequencies of the homozygous wild-types of TLR4 variants are prevalent, but homozygous mutants are rare or lacking in almost all global populations. Frequencies of the heterozygotes varied among populations. For instance, in sub-Saharan Africa the frequency of the Asp299Gly SNP is higher than that of Thr399Ile, whereas in the Arabian Peninsula both SNPs are present at high frequencies. In contrast, East Asian populations lack or have very low frequencies of both TLR4 SNPs of interest. Moreover, co-segregation of the TLR4 SNPs is common in some populations, which may indicate important associations with certain diseases. Future studies are required to link the TLR4 SNPs with either resistance or susceptibility to diseases.


Asunto(s)
Polimorfismo de Nucleótido Simple , Receptor Toll-Like 4 , Humanos , Polimorfismo de Nucleótido Simple/genética , Receptor Toll-Like 4/genética , Irán , Genotipo , Homocigoto
9.
Fungal Genet Biol ; 136: 103319, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31884054

RESUMEN

The cell wall is a distinctive feature of filamentous fungi, providing them with structural integrity and protection from both biotic and abiotic factors. Unlike plant cell walls, fungi rely on structurally strong hydrophobic chitin core for mechanical strength together with alpha- and beta-glucans, galactomannans and glycoproteins. Cell wall stress conditions are known to alter the cell wall through the signaling cascade of the cell wall integrity (CWI) pathway and can result in increased cell wall chitin deposition. A previously isolated set of Aspergillus niger cell wall mutants was screened for increased cell wall chitin deposition. UV-mutant RD15.8#16 was found to contain approximately 60% more cell wall chitin than the wild type. In addition to the chitin phenotype, RD15.8#16 exhibits a compact colony morphology and increased sensitivity towards SDS. RD15.8#16 was subjected to classical genetic approach for identification of the underlying causative mutation, using co-segregation analysis and SNP genotyping. Genome sequencing of RD15.8#16 revealed eight SNPs in open reading frames (ORF) which were individually checked for co-segregation with the associated phenotypes, and showed the potential relevance of two genes located on chromosome IV. In situ re-creation of these ORF-located SNPs in a wild type background, using CRISPR/Cas9 genome editing, showed the importance Rab GTPase dissociation inhibitor A (gdiA) for the phenotypes of RD15.8#16. An alteration in the 5' donor splice site of gdiA reduced pre-mRNA splicing efficiency, causing aberrant cell wall assembly and increased chitin levels, whereas gene disruption attempts showed that a full gene deletion of gdiA is lethal.


Asunto(s)
Aspergillus niger/genética , Quitina/metabolismo , Proteínas Fúngicas/genética , Genes Esenciales , Inhibidores de Disociación de Guanina Nucleótido/genética , Aspergillus niger/metabolismo , Sistemas CRISPR-Cas , Pared Celular/metabolismo , Eliminación de Gen , Edición Génica , Regulación Fúngica de la Expresión Génica , Genoma Fúngico , Técnicas de Genotipaje , Polimorfismo de Nucleótido Simple , Empalme del ARN/genética , Proteínas de Unión al GTP rab/genética , Proteínas de Unión al GTP rab/metabolismo
10.
Int J Legal Med ; 133(6): 1733-1742, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31455979

RESUMEN

Sudden arrhythmic death syndrome (SADS) in young individuals is a devastating and tragic event often caused by an undiagnosed inherited cardiac disease. Although post-mortem genetic testing represents a promising tool to elucidate potential disease-causing mechanisms in such autopsy-negative death cases, a variant interpretation is still challenging, and functional consequences of identified sequence alterations often remain unclear. Recently, we have identified a novel heterozygous missense variant (N1774H) in the Nav1.5 channel-encoding gene SCN5A in a 19-year-old female SADS victim. The aim of this study was to perform a co-segregation analysis in family members of the index case and to evaluate the functional consequences of this SCN5A variant. Functional characterization of the SCN5A N1774H variant was performed using patch-clamp techniques in TsA-201 cell line transiently expressing either wild-type or variant Nav1.5 channels. Electrophysiological analyses revealed that variant Nav1.5 channels show a loss-of-function in the peak current densities, but an increased late current compared to the wild-type channels, which could lead to both, loss- and gain-of-function respectively. Furthermore, clinical assessment and genetic testing of the relatives of the index case showed that all N1774H mutation carriers have prolonged QT intervals. The identification of several genotype and phenotype positive family members and the functional implication of the SCN5A N1774H variant support the evidence of the in silico predicted pathogenicity of the here reported sequence alteration.


Asunto(s)
Muerte Súbita Cardíaca/etiología , Síndrome de QT Prolongado/genética , Mutación Missense , Canal de Sodio Activado por Voltaje NAV1.5/genética , Linaje , Femenino , Genotipo , Heterocigoto , Humanos , Lactante , Masculino , Fenotipo , Secuenciación del Exoma , Adulto Joven
11.
BMC Med Genet ; 20(1): 43, 2019 03 20.
Artículo en Inglés | MEDLINE | ID: mdl-30894143

RESUMEN

BACKGROUND: To investigate the clinical features and the underlying causal gene of a family with hereditary late-onset deafness in Inner Mongolia of China, and to provide evidence for the early genetic screening and diagnosis of this disease. METHODS: Family data were collected to draw a pedigree. Audiological testing and physical examination of the family members were conducted following questionnaire. Genomic DNA was extracted from peripheral blood of 5 family members (3 patients and 2 normal control) and subjected to whole genome sequencing for identifying deafness casual genes. The pathogenic variant in the deafness gene was further confirmed by Sanger sequencing. RESULTS: The family is composed of a total of 6 generations, with 53 traceable individuals. In this family,19 of them were diagnosed with post lingual deafness with the age of onset between 10 and 40 years, displaying delayed and progressive hearing loss. Patients with hearing loss showed bilateral symmetry and mild to severe sensorineural deafness. The pattern of deafness inheritance in this family is autosomal dominant. Whole genome sequencing identified a novel pathogenic frameshift mutation, c.158_159delAA (p.Gln53Arg fs*100) in the gene OSBPL2 (Oxysterol-binding protein-related protein 2, NM_144498.2), which is absent from genomic data of 201 unrelated normal subjects. This pathogenic variant was further validated by Sanger sequencing, and was found to co-segregate in this family. CONCLUSIONS: Whole genome sequencing identified a two-nucleotide deletion in OSBPL2 (c.158_159delAA) as the pathogenic variant for deafness in the family. Our finding expands the mutational spectrum of OSBPL2 and contributes to the pathogenic variant list in genetic counseling for deafness screening.


Asunto(s)
Mutación del Sistema de Lectura , Pérdida Auditiva/congénito , Pérdida Auditiva/genética , Receptores de Esteroides/genética , Secuenciación Completa del Genoma/métodos , Adulto , Edad de Inicio , Pueblo Asiatico/genética , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Mongolia , Linaje , Fenotipo
12.
Front Genet ; 9: 725, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30745909

RESUMEN

Schizophrenia is a complex psychiatric disorder with high genetic heterogeneity, however, the contribution of rare mutations to the disease etiology remains to be further elucidated. We herein performed exome sequencing in a Han Chinese schizophrenia family and identified a missense mutation (c.6724C>T, p.R2242C) in the teneurin transmembrane protein 4 (TENM4) gene in the SCZD2 locus, a region previously linked to schizophrenia at 11q14-21. The mutation was confirmed to co-segregate with the schizophrenia phenotype in the family. Subsequent investigation of TENM4 exons 31, 32, and 33 adjacent to the p.R2242C mutation revealed two additional missense mutations in 120 sporadic schizophrenic patients. Residues mutated in these mutations, which are predicted to be deleterious to protein function, were highly conserved among vertebrates. These rare mutations were not detected in 1000 Genomes, NHLBI Exome Sequencing Project databases, or our in-house 1136 non-schizophrenic control exomes. Analysis of RNA-Seq data showed that TENM4 is expressed in the brain with high abundance and specificity. In line with the important role of TENM4 in central nervous system development, our findings suggested that increased rare variants in TENM4 could be associated with schizophrenia, and thus TENM4 could be a novel candidate gene for schizophrenia in the SCZD2 locus.

13.
J Psychiatr Res ; 85: 49-55, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27835739

RESUMEN

OBJECTIVE: The main aim of this study was to use familial risk analysis to examine the association between attention deficit hyperactivity disorder (ADHD) and substance use disorders (SUDs) attending to sex effects and the specificity of alcohol and drug use disorder risks. METHODS: Subjects were derived from two longitudinal case-control family studies of probands aged 6-17 years with and without DSM-III-R ADHD of both sexes and their first degree relatives followed from childhood onto young adult years. Cox proportional hazard models were used to estimate rates of ADHD and SUDs (any SUD, alcohol dependence, and drug dependence). Logistic regression was used to test both co-segregation and assortative mating. RESULTS: Our sample included 404 probands (ADHD: 112 boys and 96 girls; Control: 105 boys and 91 girls) and their 1336 relatives. SUDs in probands increased the risk for SUDs in relatives irrespective of ADHD status. The risk for dependence to drug or alcohol in relatives was non-specific. There was evidence that even in the absence of a SUD in the proband, ADHD by itself increased the risk of SUDs in relatives. Proband sex did not moderate the familial relationship between ADHD and SUDs. There was evidence of co-segregation between ADHD and SUD. CONCLUSIONS: Findings indicate that various independent pathways are involved in the transmission of SUD in ADHD and that these risks were not moderated by proband sex. ADHD children and siblings should benefit from preventive and early intervention strategies to decrease their elevated risk for developing a SUD.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/epidemiología , Predisposición Genética a la Enfermedad , Padres , Hermanos , Trastornos Relacionados con Sustancias/epidemiología , Adolescente , Trastorno por Déficit de Atención con Hiperactividad/genética , Estudios de Casos y Controles , Niño , Femenino , Estudios de Seguimiento , Humanos , Entrevista Psicológica , Modelos Logísticos , Estudios Longitudinales , Masculino , Padres/psicología , Modelos de Riesgos Proporcionales , Medición de Riesgo , Factores Sexuales , Hermanos/psicología , Factores Socioeconómicos , Trastornos Relacionados con Sustancias/genética
14.
Hum Mutat ; 38(3): 243-251, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27995669

RESUMEN

To interpret genetic variants discovered from next-generation sequencing, integration of heterogeneous information is vital for success. This article describes a framework named PERCH (Polymorphism Evaluation, Ranking, and Classification for a Heritable trait), available at http://BJFengLab.org/. It can prioritize disease genes by quantitatively unifying a new deleteriousness measure called BayesDel, an improved assessment of the biological relevance of genes to the disease, a modified linkage analysis, a novel rare-variant association test, and a converted variant call quality score. It supports data that contain various combinations of extended pedigrees, trios, and case-controls, and allows for a reduced penetrance, an elevated phenocopy rate, liability classes, and covariates. BayesDel is more accurate than PolyPhen2, SIFT, FATHMM, LRT, Mutation Taster, Mutation Assessor, PhyloP, GERP++, SiPhy, CADD, MetaLR, and MetaSVM. The overall approach is faster and more powerful than the existing quantitative method pVAAST, as shown by the simulations of challenging situations in finding the missing heritability of a complex disease. This framework can also classify variants of unknown significance (variants of uncertain significance) by quantitatively integrating allele frequencies, deleteriousness, association, and co-segregation. PERCH is a versatile tool for gene prioritization in gene discovery research and variant classification in clinical genetic testing.


Asunto(s)
Biología Computacional/métodos , Estudios de Asociación Genética/métodos , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple , Carácter Cuantitativo Heredable , Programas Informáticos , Humanos , Curva ROC , Reproducibilidad de los Resultados
15.
Clin Case Rep ; 4(9): 879-84, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27648268

RESUMEN

Despite co-segregation of two different genetic neurological disorders within a family is rare, clinicians should take into consideration this possibility in patients presenting with unusual complex phenotypes or with unexpected electrophysiological findings. Here, we report a Spanish 11-month-old patient with spinal muscular atrophy type 2 and Charcot-Marie-Tooth 1A.

16.
Mol Med ; 22: 560-569, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27463508

RESUMEN

We investigated the pathophysiology of diet-induced diabetes in the Cohen diabetic rat (CDs/y) from its induction to its chronic phase, using a multi-layered integrated genomic approach. We identified by linkage analysis two diabetes-related quantitative trait loci on RNO4 and RNO13. We determined their functional contribution to diabetes by chromosomal substitution, using congenic and consomic strains. To identify within these loci genes of relevance to diabetes, we sequenced the genome of CDs/y and compared it to 25 other rat strains. Within the RNO4 locus, we detected a novel high impact deletion in the Ndufa4 gene that was unique to CDs/y. Within the RNO13 locus, we found multiple SNPs and INDELs that were unique to CDs/y but were unable to prioritize any of the genes. Genome wide screening identified a novel third locus not detected by linkage analysis that consisted of a novel high impact deletion on RNO11 that was unique to CDs/y and that involved the Sdf2l1 gene. Using co-segregation analysis, we investigated in silico the relative contribution to the diabetic phenotype and the interaction between the three genomic loci on RNO4, RNO11 and RNO13. We found that the RNO4 locus plays a major role during the induction of diabetes, whereas the genomic loci on RNO13 and RNO11, while interacting with the RNO4 locus, contribute more significantly to the diabetic phenotype during the chronic phase of the disease. The mechanisms whereby the mutations on RNO4 and 11 and the RNO13 locus contribute to the development of diabetes are under continuing investigation.

17.
J Genet Couns ; 25(6): 1146-1156, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27422780

RESUMEN

Multi-gene cancer panels often identify variants of uncertain clinical significance (VUS) that pose a challenge to health care providers in managing a patient's cancer risk. Family segregation analysis can yield powerful data to re-classify a VUS (as either benign or pathogenic). However, financial and personnel resources to coordinate these studies are limited. In an informal assessment we found that family studies for variant classification are done by most clinical genetics laboratories that offer hereditary cancer panel testing. The process for family studies differs substantially across laboratories. One near universal limitation is that families usually have too few individuals for an informative co-segregation analysis. A unique and potential resource-saving approach is to engage patients and their families in expanding their own pedigrees for segregation analysis of their VUS. We describe a novel public educational tool ( FindMyVariant.org ) designed to inform patients and genetic counselors about strategies to improve the probability of variant classification using familial segregation. While the web tool is designed to be useful for any gene, the project was primarily focused on VUS's returned in cancer risk genes. FindMyVariant.org is a resource for genetic providers to offer motivated families who are willing to gather information about their family relationships and history. Working alongside clinical or research genetic laboratories, the information they collect may help reclassify their VUS using segregation analysis.


Asunto(s)
Predisposición Genética a la Enfermedad , Neoplasias/genética , Linaje , Programas Informáticos , Incertidumbre , Humanos , Internet , Neoplasias/diagnóstico , Neoplasias/psicología , Educación del Paciente como Asunto
18.
Clin Genet ; 87(5): 440-7, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-24735133

RESUMEN

Heterozygous loss-of-function mutations in the glucokinase (GCK) gene cause maturity-onset diabetes of the young (MODY) subtype GCK (GCK-MODY/MODY2). GCK sequencing revealed 16 distinct mutations (13 missense, 1 nonsense, 1 splice site, and 1 frameshift-deletion) co-segregating with hyperglycaemia in 23 GCK-MODY families. Four missense substitutions (c.718A>G/p.Asn240Asp, c.757G>T/p.Val253Phe, c.872A>C/p.Lys291Thr, and c.1151C>T/p.Ala384Val) were novel and a founder effect for the nonsense mutation (c.76C>T/p.Gln26*) was supposed. We tested whether an accurate bioinformatics approach could strengthen family-genetic evidence for missense variant pathogenicity in routine diagnostics, where wet-lab functional assays are generally unviable. In silico analyses of the novel missense variants, including orthologous sequence conservation, amino acid substitution (AAS)-pathogenicity predictors, structural modeling and splicing predictors, suggested that the AASs and/or the underlying nucleotide changes are likely to be pathogenic. This study shows how a careful bioinformatics analysis could provide effective suggestions to help molecular-genetic diagnosis in absence of wet-lab validations.


Asunto(s)
Biología Computacional , Diabetes Mellitus Tipo 2/genética , Glucoquinasa/genética , Mutación Missense , Fenotipo , Población Blanca/genética , Adolescente , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Niño , Preescolar , Biología Computacional/métodos , Análisis Mutacional de ADN , Diabetes Mellitus Tipo 2/diagnóstico , Femenino , Humanos , Masculino , Datos de Secuencia Molecular , Linaje , Alineación de Secuencia
19.
Front Oncol ; 4: 226, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25191642

RESUMEN

During tissue homeostasis, normal stem cells self-renew and repopulate the diverse cell types found within the tissue via a series of carefully controlled symmetric and asymmetric cell divisions (ACDs). The notion that solid tumors comprise a subset of cancer stem cells (CSCs) with dysregulated self-renewal and excessive symmetric cell divisions has led to numerous studies aimed to elucidate the mechanisms regulating ACD under steady-state conditions, during stem-cell expansion and in cancer. In this perspective, we focus on a type of asymmetry that can be established during ACD, called non-random co-segregation of template DNA, which has been identified across numerous species, cell types, and cancers. We discuss the role of p53 loss in maintaining self-renewal in both normal and malignant cells. We then review our current knowledge of the mechanisms underlying co-segregation of template DNA strands and the stem-cell pathways associated with it in normal and CSCs.

20.
Eur J Med Genet ; 57(10): 562-6, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25118007

RESUMEN

We report an African-American family that was identified after the proposita was referred for diagnostic evaluation at 4½ months with a history of Hirschsprung and dysmorphic features typical of Waardenburg syndrome (WS). Family evaluation revealed that the father had heterochromidia irides and hypertelorism supporting the clinical diagnosis of WS; however, examination of the mother revealed characteristic facial and digital features of Coffin-Lowry syndrome (CLS). Molecular testing of the mother identified a novel 2 bp deletion (c.865_866delCA) in codon 289 of RPS6KA3 leading to a frame-shift and premature termination of translation 5 codons downstream (NM_004586.2:p.Gln289ValfsX5). This deletion also was identified in the proposita and her three sisters with a clinical suspicion of CLS, all of whom as carriers for this X-linked disorder had very subtle manifestations. The molecular confirmation of WS type 4 (Shah-Waardenburg; WS4) was not as straightforward. To evaluate WS types 1-4, multiple sequential molecular tests were requested, including Sanger sequencing of all exons, and deletion/duplication analysis using MLPA for PAX3, MITF, SOX10, EDN3 and EDNRB. Although sequencing did not identify any disease causing variants, MLPA identified a heterozygous deletion of the entire EDNRB in the father. This deletion was also found in the proposita and the oldest child. Since the heterozygous deletion was the only change identified in EDNRB, this family represents one of the few cases of an autosomal dominant inheritance of WS4 involving the endothelin pathway. Altogether, clinical evaluation of the family revealed one child to be positive for WS4 and two positive for CLS, while two children were positive for both diseases simultaneously (including the proposita) while another pair test negative for either disease. This kinship is an example of the coincidence of two conditions co-segregating in one family, with variable phenotypes requiring molecular testing to confirm the clinical diagnoses.


Asunto(s)
Deleción Cromosómica , Síndrome de Coffin-Lowry/genética , Receptores de Endotelina/genética , Síndrome de Waardenburg/genética , Adulto , Negro o Afroamericano , Secuencia de Bases , Niño , Segregación Cromosómica , Cromosomas Humanos X , Codón , Comorbilidad , ADN , Análisis Mutacional de ADN , Exones , Femenino , Genes Dominantes , Herencia , Enfermedad de Hirschsprung , Humanos , Lactante , Masculino , Datos de Secuencia Molecular , Núcleo Familiar , Linaje , Receptor de Endotelina B
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